Non-functional changes only (#3153)

* Non-functional changes only

* Added class level comments and authors

31 files changed, 212 insertions, 107 deletions

diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/maintainer/FileHelper.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/maintainer/FileHelper.java
index 2274baf632e..db84f6af496 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/maintainer/FileHelper.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/maintainer/FileHelper.java
@@ -20,7 +20,6 @@ import java.util.stream.Collectors;
 /**
  * @author freva
  */
-
 public class FileHelper {
     private static final Logger logger = Logger.getLogger(FileHelper.class.getSimpleName());
 
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/CommandExecutor.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/CommandExecutor.java
index e1d0e46c173..eac0bc574c3 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/CommandExecutor.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/CommandExecutor.java
@@ -10,16 +10,19 @@ import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.StringReader;
 import java.util.ArrayList;
+import java.util.List;
 
 /**
- * Created by olaa on 03/07/2017.
  * Wrapper for executing terminal commands
+ *
+ * @author olaaun
+ * @author sgrostad
  */
 public class CommandExecutor {
 
-    public ArrayList<String> executeCommand(String command) throws IOException {
+    public List<String> executeCommand(String command) throws IOException {
         ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
-        ArrayList<String> results = new ArrayList<>();
+        List<String> results = new ArrayList<>();
         writeToOutputStream(outputStream, command);
         writeOutputStreamToResults(outputStream, results);
         return results;
@@ -35,7 +38,7 @@ public class CommandExecutor {
         executor.execute(cmdLine);
     }
 
-    private void writeOutputStreamToResults(ByteArrayOutputStream outputStream, ArrayList<String> results) throws IOException {
+    private void writeOutputStreamToResults(ByteArrayOutputStream outputStream, List<String> results) throws IOException {
         String out = outputStream.toString();
         BufferedReader br = new BufferedReader(new StringReader(out));
         String line;
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/HostURLGenerator.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/HostURLGenerator.java
index b43c9caed54..7e8b198428f 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/HostURLGenerator.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/HostURLGenerator.java
@@ -5,10 +5,13 @@ import java.io.IOException;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.util.ArrayList;
+import java.util.List;
 
 /**
- * Created by olaa on 14/07/2017.
  * Makes the URL used to retrieve the JSON from the node repository with information about the node's spec.
+ *
+ * @author olaaun
+ * @author sgrostad
  */
 public class HostURLGenerator {
 
@@ -18,8 +21,8 @@ public class HostURLGenerator {
     private static final String PARSE_ALL_HOSTNAMES_REGEX = ",";
     private static final String PROTOCOL_REGEX = "^(https?|file)://.*$";
 
-    public static ArrayList<URL> generateNodeInfoUrl(CommandExecutor commandExecutor, String commaSeparatedUrls) throws IOException {
-        ArrayList<URL> nodeInfoUrls = new ArrayList<>();
+    public static List<URL> generateNodeInfoUrl(CommandExecutor commandExecutor, String commaSeparatedUrls) throws IOException {
+        List<URL> nodeInfoUrls = new ArrayList<>();
         String[] configServerHostNames = commaSeparatedUrls.split(PARSE_ALL_HOSTNAMES_REGEX);
         String nodeHostName = generateNodeHostName(commandExecutor);
         for (String configServerHostName : configServerHostNames) {
@@ -34,7 +37,7 @@ public class HostURLGenerator {
     }
 
     protected static String getEnvironmentVariable(CommandExecutor commandExecutor) throws IOException {
-        ArrayList<String> output = commandExecutor.executeCommand("hostname");
+        List<String> output = commandExecutor.executeCommand("hostname");
         if (output.size() == 1) {
             return output.get(0);
         }
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/noderepo/IPAddressVerifier.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/noderepo/IPAddressVerifier.java
index 483c07002dd..db4eb6e73cd 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/noderepo/IPAddressVerifier.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/noderepo/IPAddressVerifier.java
@@ -12,14 +12,17 @@ import javax.naming.directory.InitialDirContext;
 import java.util.ArrayList;
 import java.util.Enumeration;
 import java.util.Hashtable;
+import java.util.List;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
 /**
  * Created by olaa on 14/07/2017.
  * Verifies that the IP addresses of a node points to the correct hostname
+ * 
+ * @author olaaun
+ * @author sgrostad
  */
-
 public class IPAddressVerifier {
 
     private static final Logger logger = Logger.getLogger(IPAddressVerifier.class.getName());
@@ -33,7 +36,7 @@ public class IPAddressVerifier {
 
     public String[] getFaultyIpAddresses(NodeRepoJsonModel jsonModel) {
         String expectedHostname = jsonModel.getHostname();
-        ArrayList<String> faultyIpAddresses = new ArrayList<>();
+        List<String> faultyIpAddresses = new ArrayList<>();
         if (expectedHostname == null || expectedHostname.equals(""))
             return new String[0];
         if (!isValidIpv4(jsonModel.getIpv4Address(), expectedHostname)) {
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/noderepo/NodeJsonConverter.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/noderepo/NodeJsonConverter.java
index ef6d706a1a4..5cf4bede3f1 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/noderepo/NodeJsonConverter.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/noderepo/NodeJsonConverter.java
@@ -4,8 +4,10 @@ package com.yahoo.vespa.hosted.node.verification.commons.noderepo;
 import com.yahoo.vespa.hosted.node.verification.spec.retrievers.HardwareInfo;
 
 /**
- * Created by olaa on 07/07/2017.
  * Converts a NodeRepoJsonModel object to a HardwareInfo object.
+ * 
+ * @author olaaun
+ * @author sgrostad
  */
 public class NodeJsonConverter {
 
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/noderepo/NodeRepoInfoRetriever.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/noderepo/NodeRepoInfoRetriever.java
index 4d261334d35..57506e44961 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/noderepo/NodeRepoInfoRetriever.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/noderepo/NodeRepoInfoRetriever.java
@@ -6,18 +6,21 @@ import com.fasterxml.jackson.databind.ObjectMapper;
 import java.io.IOException;
 import java.net.URL;
 import java.util.ArrayList;
+import java.util.List;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
 /**
- * Created by olaa on 04/07/2017.
  * Parse JSON from node repository and stores information as a NodeRepoJsonModel object.
+ *
+ * @author olaaun
+ * @author sgrostad
  */
 public class NodeRepoInfoRetriever {
 
     private static final Logger logger = Logger.getLogger(NodeRepoInfoRetriever.class.getName());
 
-    public static NodeRepoJsonModel retrieve(ArrayList<URL> nodeInfoUrls) throws IOException {
+    public static NodeRepoJsonModel retrieve(List<URL> nodeInfoUrls) throws IOException {
         NodeRepoJsonModel nodeRepoJsonModel;
         ObjectMapper objectMapper = new ObjectMapper();
         for (URL nodeInfoURL : nodeInfoUrls) {
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/noderepo/NodeRepoJsonModel.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/noderepo/NodeRepoJsonModel.java
index 043cccb681c..5d7ff0df8d1 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/noderepo/NodeRepoJsonModel.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/noderepo/NodeRepoJsonModel.java
@@ -13,12 +13,14 @@ import java.net.InetAddress;
 import java.util.stream.Stream;
 
 /**
- * Created by olaa on 05/07/2017.
  * Object with the information node repositories has about the node.
+ *
+ * @author olaaun
+ * @author sgrostad
  */
-
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class NodeRepoJsonModel {
+
     @JsonProperty("minDiskAvailableGb")
     private double minDiskAvailableGb;
     @JsonProperty("minMainMemoryAvailableGb")
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/parser/OutputParser.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/parser/OutputParser.java
index 88e1d22cc0e..5da5abd4ad2 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/parser/OutputParser.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/parser/OutputParser.java
@@ -2,19 +2,22 @@
 package com.yahoo.vespa.hosted.node.verification.commons.parser;
 
 import java.util.ArrayList;
+import java.util.List;
 import java.util.regex.Pattern;
 
 /**
- * Created by sgrostad on 17/07/2017.
  * Parses terminal command output, and returns results based on ParseInstructions
+ *
+ * @author sgrostad
+ * @author olaaaun
  */
 public class OutputParser {
 
-    public static ArrayList<ParseResult> parseOutput(ParseInstructions parseInstructions, ArrayList<String> commandOutput) {
-        ArrayList<ParseResult> results = new ArrayList<>();
+    public static List<ParseResult> parseOutput(ParseInstructions parseInstructions, List<String> commandOutput) {
+        List<ParseResult> results = new ArrayList<>();
         int searchElementIndex = parseInstructions.getSearchElementIndex();
         int valueElementIndex = parseInstructions.getValueElementIndex();
-        ArrayList<String> searchWords = parseInstructions.getSearchWords();
+        List<String> searchWords = parseInstructions.getSearchWords();
         for (String line : commandOutput) {
             String[] lineSplit = line.trim().split(parseInstructions.getSplitRegex());
             if (lineSplit.length <= Math.max(searchElementIndex, valueElementIndex)) {
@@ -30,15 +33,15 @@ public class OutputParser {
         return results;
     }
 
-    public static ParseResult parseSingleOutput(ParseInstructions parseInstructions, ArrayList<String> commandOutput) {
-        ArrayList<ParseResult> parseResults = parseOutput(parseInstructions, commandOutput);
+    public static ParseResult parseSingleOutput(ParseInstructions parseInstructions, List<String> commandOutput) {
+        List<ParseResult> parseResults = parseOutput(parseInstructions, commandOutput);
         if (parseResults.size() == 0) {
             return new ParseResult("invalid", "invalid");
         }
         return parseResults.get(0);
     }
 
-    private static boolean matchingSearchWord(ArrayList<String> searchWords, String searchWordCandidate) {
+    private static boolean matchingSearchWord(List<String> searchWords, String searchWordCandidate) {
         return searchWords.stream().anyMatch(w -> Pattern.compile(w).matcher(searchWordCandidate).matches());
     }
 
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/parser/ParseInstructions.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/parser/ParseInstructions.java
index 6fb962c8232..262bfcba0b9 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/parser/ParseInstructions.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/parser/ParseInstructions.java
@@ -1,19 +1,22 @@
 // Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.node.verification.commons.parser;
 
-import java.util.ArrayList;
+import java.util.List;
 
 /**
- * Created by sgrostad on 17/07/2017.
+ * Contains instructions of how a command line output should be parsed
+ *
+ * @author sgrostad
+ * @author olaaaun
  */
 public class ParseInstructions {
 
     private final int searchElementIndex;
     private final int valueElementIndex;
     private final String splitRegex;
-    private final ArrayList<String> searchWords;
+    private final List<String> searchWords;
 
-    public ParseInstructions(int searchElementIndex, int returnElementNum, String splitRegex, ArrayList<String> searchWords) {
+    public ParseInstructions(int searchElementIndex, int returnElementNum, String splitRegex, List<String> searchWords) {
         this.searchElementIndex = searchElementIndex;
         this.valueElementIndex = returnElementNum;
         this.splitRegex = splitRegex;
@@ -32,7 +35,7 @@ public class ParseInstructions {
         return splitRegex;
     }
 
-    public ArrayList<String> getSearchWords() {
+    public List<String> getSearchWords() {
         return searchWords;
     }
 
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/parser/ParseResult.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/parser/ParseResult.java
index df16897066b..a89cfd89f31 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/parser/ParseResult.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/parser/ParseResult.java
@@ -4,7 +4,10 @@ package com.yahoo.vespa.hosted.node.verification.commons.parser;
 import java.util.Objects;
 
 /**
- * Created by sgrostad on 17/07/2017.
+ * Contains the results from parsing a command line output
+ *
+ * @author sgrostad
+ * @author olaaun
  */
 public class ParseResult {
 
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/report/BenchmarkReport.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/report/BenchmarkReport.java
index f27d132df42..ce4e3685a25 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/report/BenchmarkReport.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/report/BenchmarkReport.java
@@ -8,8 +8,10 @@ import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
 
 /**
- * Created by sgrostad on 12/07/2017.
  * JSON-mapped class for reporting benchmark results to node repo
+ * 
+ * @author sgrostad
+ * @author olaaun
  */
 @JsonInclude(JsonInclude.Include.NON_NULL)
 public class BenchmarkReport {
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/report/HardwareDivergenceReport.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/report/HardwareDivergenceReport.java
index 953a052ccfc..11830c24cef 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/report/HardwareDivergenceReport.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/report/HardwareDivergenceReport.java
@@ -5,6 +5,12 @@ import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 
+/**
+ * JSON-wrapped report for node repo
+ *
+ * @author sgrostad
+ * @author olaaun
+ */
 @JsonInclude(JsonInclude.Include.NON_NULL)
 public class HardwareDivergenceReport {
 
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/report/Reporter.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/report/Reporter.java
index 87644cb90d0..11835cab14b 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/report/Reporter.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/report/Reporter.java
@@ -8,9 +8,16 @@ import com.yahoo.vespa.hosted.node.verification.commons.noderepo.NodeRepoJsonMod
 import java.io.IOException;
 import java.net.URL;
 import java.util.ArrayList;
+import java.util.List;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
+/**
+ * Responsible for printing hardware divergence report to standard out
+ *
+ * @author sgrostad
+ * @author olaaun
+ */
 public class Reporter {
 
     private static final Logger logger = Logger.getLogger(Reporter.class.getName());
@@ -26,19 +33,19 @@ public class Reporter {
         System.out.print(report);
     }
 
-    public static void reportBenchmarkResults(BenchmarkReport benchmarkReport, ArrayList<URL> nodeInfoUrls) throws IOException {
+    public static void reportBenchmarkResults(BenchmarkReport benchmarkReport, List<URL> nodeInfoUrls) throws IOException {
         HardwareDivergenceReport hardwareDivergenceReport = generateHardwareDivergenceReport(nodeInfoUrls);
         hardwareDivergenceReport.setBenchmarkReport(benchmarkReport);
         printHardwareDivergenceReport(hardwareDivergenceReport);
     }
 
-    public static void reportSpecVerificationResults(SpecVerificationReport specVerificationReport, ArrayList<URL> nodeInfoUrls) throws IOException {
+    public static void reportSpecVerificationResults(SpecVerificationReport specVerificationReport, List<URL> nodeInfoUrls) throws IOException {
         HardwareDivergenceReport hardwareDivergenceReport = generateHardwareDivergenceReport(nodeInfoUrls);
         hardwareDivergenceReport.setSpecVerificationReport(specVerificationReport);
         printHardwareDivergenceReport(hardwareDivergenceReport);
     }
 
-    private static HardwareDivergenceReport generateHardwareDivergenceReport(ArrayList<URL> nodeInfoUrls) throws IOException {
+    private static HardwareDivergenceReport generateHardwareDivergenceReport(List<URL> nodeInfoUrls) throws IOException {
         NodeRepoJsonModel nodeRepoJsonModel = NodeRepoInfoRetriever.retrieve(nodeInfoUrls);
         ObjectMapper om = new ObjectMapper();
         if (nodeRepoJsonModel.getHardwareDivergence() == null || nodeRepoJsonModel.getHardwareDivergence().equals("null")) {
@@ -52,4 +59,5 @@ public class Reporter {
             return new HardwareDivergenceReport();
         }
     }
+
 }
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/report/SpecVerificationReport.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/report/SpecVerificationReport.java
index 424b591652b..ef99208a7ce 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/report/SpecVerificationReport.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/commons/report/SpecVerificationReport.java
@@ -13,6 +13,9 @@ import com.yahoo.vespa.hosted.node.verification.spec.retrievers.HardwareInfo;
  * Stores results of caomparing node repo spec and actual hardware info.
  * In case of divergent values, set the corresponding attribute to the actual hardware info value.
  * Attributes of equal value remain null.
+ *
+ * @author sgrostad
+ * @author olaaun
  */
 @JsonInclude(JsonInclude.Include.NON_NULL)
 public class SpecVerificationReport {
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/BenchmarkResultInspector.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/BenchmarkResultInspector.java
index 30592c59151..4989c574ed4 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/BenchmarkResultInspector.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/BenchmarkResultInspector.java
@@ -4,6 +4,12 @@ package com.yahoo.vespa.hosted.node.verification.hardware;
 import com.yahoo.vespa.hosted.node.verification.commons.report.BenchmarkReport;
 import com.yahoo.vespa.hosted.node.verification.hardware.benchmarks.BenchmarkResults;
 
+/**
+ * Responsible for checking the benchmarks results, and adding unreasonable results to BenchmarkReport
+ *
+ * @author sgrostad
+ * @author olaaun
+ */
 public class BenchmarkResultInspector {
 
     private static final double CPU_FREQUENCY_LOWER_LIMIT = 0.5;
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/HardwareBenchmarker.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/HardwareBenchmarker.java
index e332804e880..7e151a6a87e 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/HardwareBenchmarker.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/HardwareBenchmarker.java
@@ -16,6 +16,7 @@ import java.io.IOException;
 import java.net.URL;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -26,9 +27,9 @@ public class HardwareBenchmarker {
 
     private static final Logger logger = Logger.getLogger(HardwareBenchmarker.class.getName());
 
-    public static boolean hardwareBenchmarks(CommandExecutor commandExecutor, ArrayList<URL> nodeInfoUrls) throws IOException {
+    public static boolean hardwareBenchmarks(CommandExecutor commandExecutor, List<URL> nodeInfoUrls) throws IOException {
         BenchmarkResults benchmarkResults = new BenchmarkResults();
-        ArrayList<Benchmark> benchmarks = new ArrayList<>(Arrays.asList(
+        List<Benchmark> benchmarks = new ArrayList<>(Arrays.asList(
                 new DiskBenchmark(benchmarkResults, commandExecutor),
                 new CPUBenchmark(benchmarkResults, commandExecutor),
                 new MemoryBenchmark(benchmarkResults, commandExecutor)));
@@ -43,7 +44,7 @@ public class HardwareBenchmarker {
     public static void main(String[] args) throws IOException {
         LogSetup.initVespaLogging("hardware-benchmarker");
         CommandExecutor commandExecutor = new CommandExecutor();
-        ArrayList<URL> nodeInfoUrls;
+        List<URL> nodeInfoUrls;
         if (args.length == 0) {
             throw new IllegalStateException("Expected config server URL as parameter");
         }
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/benchmarks/Benchmark.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/benchmarks/Benchmark.java
index c1791ef45bd..1e5b512f492 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/benchmarks/Benchmark.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/benchmarks/Benchmark.java
@@ -2,10 +2,14 @@
 package com.yahoo.vespa.hosted.node.verification.hardware.benchmarks;
 
 /**
- * Created by sgrostad on 11/07/2017.
+ * @author sgrostad
+ * @author olaaun
  */
 public interface Benchmark {
 
+    /**
+     * Should perform benchmark for some part of the hardware, and store the result in BenchmarkResults instance passed to class
+     */
     void doBenchmark();
 
 }
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/benchmarks/BenchmarkResults.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/benchmarks/BenchmarkResults.java
index 999af15da09..dfa436460e1 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/benchmarks/BenchmarkResults.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/benchmarks/BenchmarkResults.java
@@ -2,9 +2,12 @@
 package com.yahoo.vespa.hosted.node.verification.hardware.benchmarks;
 
 /**
- * Created by sgrostad on 11/07/2017.
  * Stores results from benchmarks
+ * 
+ * @author sgrostad
+ * @author olaaun
  */
+// TODO: This should be immutable
 public class BenchmarkResults {
 
     private double cpuCyclesPerSec;
@@ -12,7 +15,6 @@ public class BenchmarkResults {
     private double memoryWriteSpeedGBs;
     private double memoryReadSpeedGBs;
 
-
     public double getMemoryWriteSpeedGBs() {
         return memoryWriteSpeedGBs;
     }
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/benchmarks/CPUBenchmark.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/benchmarks/CPUBenchmark.java
index e70385bb3a2..a55a92ba8a3 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/benchmarks/CPUBenchmark.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/benchmarks/CPUBenchmark.java
@@ -9,11 +9,15 @@ import com.yahoo.vespa.hosted.node.verification.commons.parser.ParseResult;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
 /**
- * Created by sgrostad on 11/07/2017.
+ * Responsible for benchmarking CPU clock frequency, and storing the result in a BenchmarkResults instance
+ *
+ * @author sgrostad
+ * @author olaaun
  */
 public class CPUBenchmark implements Benchmark {
 
@@ -33,31 +37,32 @@ public class CPUBenchmark implements Benchmark {
         this.commandExecutor = commandExecutor;
     }
 
+    @Override
     public void doBenchmark() {
         try {
-            ArrayList<String> commandOutput = commandExecutor.executeCommand(CPU_BENCHMARK_COMMAND);
-            ArrayList<ParseResult> parseResults = parseCpuCyclesPerSec(commandOutput);
+            List<String> commandOutput = commandExecutor.executeCommand(CPU_BENCHMARK_COMMAND);
+            List<ParseResult> parseResults = parseCpuCyclesPerSec(commandOutput);
             setCpuCyclesPerSec(parseResults);
         } catch (IOException e) {
             logger.log(Level.WARNING, "Failed to perform CPU benchmark", e);
         }
     }
 
-    protected ArrayList<ParseResult> parseCpuCyclesPerSec(ArrayList<String> commandOutput) {
-        ArrayList<String> searchWords = new ArrayList<>(Arrays.asList(CYCLES_SEARCH_WORD, SECONDS_SEARCH_WORD));
+    protected List<ParseResult> parseCpuCyclesPerSec(List<String> commandOutput) {
+        List<String> searchWords = new ArrayList<>(Arrays.asList(CYCLES_SEARCH_WORD, SECONDS_SEARCH_WORD));
         ParseInstructions parseInstructions = new ParseInstructions(SEARCH_ELEMENT_INDEX, RETURN_ELEMENT_INDEX, SPLIT_REGEX_STRING, searchWords);
         return OutputParser.parseOutput(parseInstructions, commandOutput);
     }
 
 
-    protected void setCpuCyclesPerSec(ArrayList<ParseResult> parseResults) {
+    protected void setCpuCyclesPerSec(List<ParseResult> parseResults) {
         double cpuCyclesPerSec = getCyclesPerSecond(parseResults);
         if (cpuCyclesPerSec > 0) {
             benchmarkResults.setCpuCyclesPerSec(cpuCyclesPerSec);
         }
     }
 
-    protected double getCyclesPerSecond(ArrayList<ParseResult> parseResults) {
+    protected double getCyclesPerSecond(List<ParseResult> parseResults) {
         double cycles = -1;
         double seconds = -1;
         for (ParseResult parseResult : parseResults) {
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/benchmarks/DiskBenchmark.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/benchmarks/DiskBenchmark.java
index ff8e1f21612..2a4c8d9b694 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/benchmarks/DiskBenchmark.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/benchmarks/DiskBenchmark.java
@@ -9,12 +9,16 @@ import com.yahoo.vespa.hosted.node.verification.commons.parser.ParseResult;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
 
 /**
- * Created by olaa on 10/07/2017.
+ * Responsible for benchmarking disk write speed, and storing the result in a BenchmarkResults instance
+ *
+ * @author olaaun
+ * @author sgrostad
  */
 public class DiskBenchmark implements Benchmark {
 
@@ -34,9 +38,10 @@ public class DiskBenchmark implements Benchmark {
         this.commandExecutor = commandExecutor;
     }
 
+    @Override
     public void doBenchmark() {
         try {
-            ArrayList<String> commandOutput = commandExecutor.executeCommand(DISK_BENCHMARK_COMMAND);
+            List<String> commandOutput = commandExecutor.executeCommand(DISK_BENCHMARK_COMMAND);
             ParseResult parseResult = parseDiskSpeed(commandOutput);
             setDiskSpeed(parseResult);
         } catch (IOException e) {
@@ -44,8 +49,8 @@ public class DiskBenchmark implements Benchmark {
         }
     }
 
-    protected ParseResult parseDiskSpeed(ArrayList<String> commandOutput) {
-        ArrayList<String> searchWords = new ArrayList<>(Arrays.asList(KILO_BYTE_SEARCH_WORD, MEGA_BYTE_SEARCH_WORD, GIGA_BYTE_SEARCH_WORD));
+    protected ParseResult parseDiskSpeed(List<String> commandOutput) {
+        List<String> searchWords = new ArrayList<>(Arrays.asList(KILO_BYTE_SEARCH_WORD, MEGA_BYTE_SEARCH_WORD, GIGA_BYTE_SEARCH_WORD));
         ParseInstructions parseInstructions = new ParseInstructions(SEARCH_ELEMENT_INDEX, RETURN_ELEMENT_INDEX, SPLIT_REGEX_STRING, searchWords);
         return OutputParser.parseSingleOutput(parseInstructions, commandOutput);
     }
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/benchmarks/MemoryBenchmark.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/benchmarks/MemoryBenchmark.java
index 0aa4bc28eb1..b701d9a02f8 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/benchmarks/MemoryBenchmark.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/hardware/benchmarks/MemoryBenchmark.java
@@ -9,11 +9,15 @@ import com.yahoo.vespa.hosted.node.verification.commons.parser.ParseResult;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
 /**
- * Created by sgrostad on 11/07/2017.
+ * Responsible for benchmarking memory read/write speed, and storing the result in a BenchmarkResults instance
+ *
+ * @author sgrostad
+ * @author olaaun
  */
 public class MemoryBenchmark implements Benchmark {
 
@@ -36,10 +40,11 @@ public class MemoryBenchmark implements Benchmark {
         this.commandExecutor = commandExecutor;
     }
 
+    @Override
     public void doBenchmark() {
         try {
             setupMountPoint();
-            ArrayList<String> commandOutput = commandExecutor.executeCommand(MEM_BENCHMARK_WRITE_SPEED);
+            List<String> commandOutput = commandExecutor.executeCommand(MEM_BENCHMARK_WRITE_SPEED);
             ParseResult parseResult = parseMemorySpeed(commandOutput);
             updateMemoryWriteSpeed(parseResult.getValue());
             commandOutput = commandExecutor.executeCommand(MEM_BENCHMARK_READ_SPEED);
@@ -70,8 +75,8 @@ public class MemoryBenchmark implements Benchmark {
         }
     }
 
-    protected ParseResult parseMemorySpeed(ArrayList<String> commandOutput) {
-        ArrayList<String> searchWords = new ArrayList<>(Arrays.asList(READ_AND_WRITE_SEARCH_WORD));
+    protected ParseResult parseMemorySpeed(List<String> commandOutput) {
+        List<String> searchWords = new ArrayList<>(Arrays.asList(READ_AND_WRITE_SEARCH_WORD));
         ParseInstructions parseInstructions = new ParseInstructions(SEARCH_ELEMENT_INDEX, RETURN_ELEMENT_INDEX, SPLIT_REGEX_STRING, searchWords);
         return OutputParser.parseSingleOutput(parseInstructions, commandOutput);
     }
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/HardwareNodeComparator.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/HardwareNodeComparator.java
index 0885dbafcac..88bd0539ccd 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/HardwareNodeComparator.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/HardwareNodeComparator.java
@@ -6,8 +6,10 @@ import com.yahoo.vespa.hosted.node.verification.spec.retrievers.HardwareInfo;
 import com.yahoo.vespa.hosted.node.verification.spec.retrievers.HardwareInfo.DiskType;
 
 /**
- * Created by olaa on 04/07/2017.
  * Compares two HardwareInfo objects and stores divergent values in a SpecVerificationReport
+ *
+ * @author olaaun
+ * @author sgrostad
  */
 public class HardwareNodeComparator {
 
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/SpecVerifier.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/SpecVerifier.java
index ee76cb7884e..e4cae4d7e9e 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/SpecVerifier.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/SpecVerifier.java
@@ -16,20 +16,22 @@ import com.yahoo.vespa.hosted.node.verification.spec.retrievers.HardwareInfoRetr
 import java.io.IOException;
 import java.net.URL;
 import java.util.ArrayList;
+import java.util.List;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
 /**
- * Created by olaa on 14/07/2017.
  * Creates two HardwareInfo objects, one with spec from node repository and one from spec retrieved at the node.
  * Compares the objects and returns the result.
+ *
+ * @author olaaun
+ * @author sgrostad
  */
 public class SpecVerifier {
 
     private static final Logger logger = Logger.getLogger(SpecVerifier.class.getName());
-    private static final String VIRTUAL_ENVIRONMENT = "VIRTUAL_MACHINE";
 
-    public static boolean verifySpec(CommandExecutor commandExecutor, ArrayList<URL> nodeInfoUrls) throws IOException {
+    public static boolean verifySpec(CommandExecutor commandExecutor, List<URL> nodeInfoUrls) throws IOException {
         NodeRepoJsonModel nodeRepoJsonModel = getNodeRepositoryJSON(nodeInfoUrls);
         VerifierSettings verifierSettings = new VerifierSettings(nodeRepoJsonModel);
         HardwareInfo actualHardware = HardwareInfoRetriever.retrieve(commandExecutor, verifierSettings);
@@ -45,7 +47,7 @@ public class SpecVerifier {
         return specVerificationReport;
     }
 
-    protected static NodeRepoJsonModel getNodeRepositoryJSON(ArrayList<URL> nodeInfoUrls) throws IOException {
+    protected static NodeRepoJsonModel getNodeRepositoryJSON(List<URL> nodeInfoUrls) throws IOException {
         NodeRepoJsonModel nodeRepoJsonModel = NodeRepoInfoRetriever.retrieve(nodeInfoUrls);
         return nodeRepoJsonModel;
     }
@@ -53,7 +55,7 @@ public class SpecVerifier {
     public static void main(String[] args) {
         LogSetup.initVespaLogging("spec-verifier");
         CommandExecutor commandExecutor = new CommandExecutor();
-        ArrayList<URL> nodeInfoUrls;
+        List<URL> nodeInfoUrls;
         if (args.length == 0) {
             throw new IllegalStateException("Expected config server URL as parameter");
         }
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/VerifierSettings.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/VerifierSettings.java
index 357af559014..2b5a19ce818 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/VerifierSettings.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/VerifierSettings.java
@@ -4,10 +4,11 @@ package com.yahoo.vespa.hosted.node.verification.spec;
 import com.yahoo.vespa.hosted.node.verification.commons.noderepo.NodeRepoJsonModel;
 
 /**
- * Created by sgrostad on 07/08/2017.
  * Contains information on what spec should be verified or not.
+ * 
+ * @author sgrostad
+ * @author olaaun
  */
-
 public class VerifierSettings {
 
     private final boolean checkIPv6;
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/CPURetriever.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/CPURetriever.java
index b02f37533da..b8ae5d89b55 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/CPURetriever.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/CPURetriever.java
@@ -9,11 +9,15 @@ import com.yahoo.vespa.hosted.node.verification.commons.parser.ParseResult;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
 /**
- * Created by olaa on 30/06/2017.
+ * Retrieves number of CPU cores, and stores the result in a HardwareInfo instance
+ *
+ * @author olaaun
+ * @author sgrostad
  */
 public class CPURetriever implements HardwareRetriever {
 
@@ -31,28 +35,29 @@ public class CPURetriever implements HardwareRetriever {
         this.commandExecutor = commandExecutor;
     }
 
+    @Override
     public void updateInfo() {
         try {
-            ArrayList<String> commandOutput = commandExecutor.executeCommand(CPU_INFO_COMMAND);
-            ArrayList<ParseResult> parseResults = parseCPUInfoFile(commandOutput);
+            List<String> commandOutput = commandExecutor.executeCommand(CPU_INFO_COMMAND);
+            List<ParseResult> parseResults = parseCPUInfoFile(commandOutput);
             setCpuCores(parseResults);
         } catch (IOException e) {
             logger.log(Level.WARNING, "Failed to retrieve CPU info", e);
         }
     }
 
-    protected ArrayList<ParseResult> parseCPUInfoFile(ArrayList<String> commandOutput) {
-        ArrayList<String> searchWords = new ArrayList<>(Arrays.asList(SEARCH_WORD));
+    protected List<ParseResult> parseCPUInfoFile(List<String> commandOutput) {
+        List<String> searchWords = new ArrayList<>(Arrays.asList(SEARCH_WORD));
         ParseInstructions parseInstructions = new ParseInstructions(SEARCH_ELEMENT_INDEX, RETURN_ELEMENT_INDEX, REGEX_SPLIT, searchWords);
-        ArrayList<ParseResult> parseResults = OutputParser.parseOutput(parseInstructions, commandOutput);
+        List<ParseResult> parseResults = OutputParser.parseOutput(parseInstructions, commandOutput);
         return parseResults;
     }
 
-    protected void setCpuCores(ArrayList<ParseResult> parseResults) {
+    protected void setCpuCores(List<ParseResult> parseResults) {
         hardwareInfo.setMinCpuCores(countCpuCores(parseResults));
     }
 
-    protected int countCpuCores(ArrayList<ParseResult> parseResults) {
+    protected int countCpuCores(List<ParseResult> parseResults) {
         return parseResults.size();
     }
 
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/DiskRetriever.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/DiskRetriever.java
index 2b1f7cf6a77..c86bdee18df 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/DiskRetriever.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/DiskRetriever.java
@@ -10,13 +10,18 @@ import com.yahoo.vespa.hosted.node.verification.spec.retrievers.HardwareInfo.Dis
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
 /**
- * Created by olaa on 30/06/2017.
+ * Retrieves disk space and type, and stores the result in a HardwareInfo instance
+ *
+ * @author olaaun
+ * @author sgrostad
  */
 public class DiskRetriever implements HardwareRetriever {
+
     private static final String DISK_CHECK_TYPE = "lsblk -d -o name,rota";
     private static final String DISK_CHECK_SIZE = "pvdisplay --units G | grep 'PV Size'";
     private static final String DISK_NAME = "sda";
@@ -37,6 +42,7 @@ public class DiskRetriever implements HardwareRetriever {
         this.commandExecutor = commandExecutor;
     }
 
+    @Override
     public void updateInfo() {
         updateDiskType();
         updateDiskSize();
@@ -44,7 +50,7 @@ public class DiskRetriever implements HardwareRetriever {
 
     protected void updateDiskType() {
         try {
-            ArrayList<String> commandOutput = commandExecutor.executeCommand(DISK_CHECK_TYPE);
+            List<String> commandOutput = commandExecutor.executeCommand(DISK_CHECK_TYPE);
             ParseResult parseResult = parseDiskType(commandOutput);
             setDiskType(parseResult);
         } catch (IOException e) {
@@ -54,16 +60,16 @@ public class DiskRetriever implements HardwareRetriever {
 
     protected void updateDiskSize() {
         try {
-            ArrayList<String> commandOutput = commandExecutor.executeCommand(DISK_CHECK_SIZE);
-            ArrayList<ParseResult> parseResult = parseDiskSize(commandOutput);
+            List<String> commandOutput = commandExecutor.executeCommand(DISK_CHECK_SIZE);
+            List<ParseResult> parseResult = parseDiskSize(commandOutput);
             setDiskSize(parseResult);
         } catch (IOException e) {
             logger.log(Level.WARNING, "Failed to retrieve disk size", e);
         }
     }
 
-    protected ParseResult parseDiskType(ArrayList<String> commandOutput) throws IOException {
-        ArrayList<String> searchWords = new ArrayList<>(Arrays.asList(DISK_NAME));
+    protected ParseResult parseDiskType(List<String> commandOutput) throws IOException {
+        List<String> searchWords = new ArrayList<>(Arrays.asList(DISK_NAME));
         ParseInstructions parseInstructions = new ParseInstructions(DISK_TYPE_SEARCH_ELEMENT_INDEX, DISK_TYPE_RETURN_ELEMENT_INDEX, DISK_TYPE_REGEX_SPLIT, searchWords);
         ParseResult parseResult = OutputParser.parseSingleOutput(parseInstructions, commandOutput);
         if (!parseResult.getSearchWord().equals(DISK_NAME)) {
@@ -83,13 +89,13 @@ public class DiskRetriever implements HardwareRetriever {
         }
     }
 
-    protected ArrayList<ParseResult> parseDiskSize(ArrayList<String> commandOutput) {
-        ArrayList<String> searchWords = new ArrayList<>(Arrays.asList(DISK_SIZE_SEARCH_WORD));
+    protected List<ParseResult> parseDiskSize(List<String> commandOutput) {
+        List<String> searchWords = new ArrayList<>(Arrays.asList(DISK_SIZE_SEARCH_WORD));
         ParseInstructions parseInstructions = new ParseInstructions(DISK_SIZE_SEARCH_ELEMENT_INDEX, DISK_SIZE_RETURN_ELEMENT_INDEX, DISK_SIZE_REGEX_SPLIT, searchWords);
         return OutputParser.parseOutput(parseInstructions, commandOutput);
     }
 
-    protected void setDiskSize(ArrayList<ParseResult> parseResults) {
+    protected void setDiskSize(List<ParseResult> parseResults) {
         double diskSize = 0;
         try {
             for (ParseResult parseResult : parseResults) {
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/HardwareInfo.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/HardwareInfo.java
index 8d726c507ba..1c17d73523b 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/HardwareInfo.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/HardwareInfo.java
@@ -2,10 +2,12 @@
 package com.yahoo.vespa.hosted.node.verification.spec.retrievers;
 
 /**
- * Created by olaa on 04/07/2017.
  * All information the different retrievers retrieve is stored as a HardwareInfo object.
+ *
+ * @author olaaun
+ * @author sgrostad
  */
-
+// TODO: This should be immutable
 public class HardwareInfo {
 
     private double minDiskAvailableGb;
@@ -17,7 +19,6 @@ public class HardwareInfo {
     private double interfaceSpeedMbs;
     private DiskType diskType;
 
-
     public double getInterfaceSpeedMbs() {
         return interfaceSpeedMbs;
     }
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/HardwareInfoRetriever.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/HardwareInfoRetriever.java
index e3235590169..ba29f07baeb 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/HardwareInfoRetriever.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/HardwareInfoRetriever.java
@@ -5,16 +5,19 @@ import com.yahoo.vespa.hosted.node.verification.commons.CommandExecutor;
 import com.yahoo.vespa.hosted.node.verification.spec.VerifierSettings;
 
 import java.util.ArrayList;
+import java.util.List;
 
 /**
- * Created by olaa on 30/06/2017.
  * Makes a HardwareInfo object and calls all the retrievers for this object.
+ *
+ * @author olaaun
+ * @author sgrostad
  */
 public class HardwareInfoRetriever {
 
     public static HardwareInfo retrieve(CommandExecutor commandExecutor, VerifierSettings verifierSettings) {
         HardwareInfo hardwareInfo = new HardwareInfo();
-        ArrayList<HardwareRetriever> infoList = new ArrayList<>();
+        List<HardwareRetriever> infoList = new ArrayList<>();
         infoList.add(new CPURetriever(hardwareInfo, commandExecutor));
         infoList.add(new MemoryRetriever(hardwareInfo, commandExecutor));
         infoList.add(new DiskRetriever(hardwareInfo, commandExecutor));
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/HardwareRetriever.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/HardwareRetriever.java
index 90e00560e59..d77342db982 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/HardwareRetriever.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/HardwareRetriever.java
@@ -2,10 +2,14 @@
 package com.yahoo.vespa.hosted.node.verification.spec.retrievers;
 
 /**
- * Created by olaa on 30/06/2017.
+ * @author olaaun
+ * @author sgrostad
  */
 public interface HardwareRetriever {
 
+    /**
+     * Should retrieve spec from some part of the hardware, and store the result in hardwareinfo instance passed to class
+     */
     void updateInfo();
 
 }
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/MemoryRetriever.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/MemoryRetriever.java
index 2a64e0f4b21..c6655e13797 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/MemoryRetriever.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/MemoryRetriever.java
@@ -9,11 +9,15 @@ import com.yahoo.vespa.hosted.node.verification.commons.parser.ParseResult;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
 /**
- * Created by olaa on 30/06/2017.
+ * Retrieves memory size, and stores the result in a HardwareInfo instance
+ *
+ * @author olaaun
+ * @author sgrostad
  */
 public class MemoryRetriever implements HardwareRetriever {
 
@@ -31,10 +35,10 @@ public class MemoryRetriever implements HardwareRetriever {
         this.commandExecutor = commandExecutor;
     }
 
-
+    @Override
     public void updateInfo() {
         try {
-            ArrayList<String> commandOutput = commandExecutor.executeCommand(MEMORY_INFO_COMMAND);
+            List<String> commandOutput = commandExecutor.executeCommand(MEMORY_INFO_COMMAND);
             ParseResult parseResult = parseMemInfoFile(commandOutput);
             updateMemoryInfo(parseResult);
         } catch (IOException e) {
@@ -42,8 +46,8 @@ public class MemoryRetriever implements HardwareRetriever {
         }
     }
 
-    protected ParseResult parseMemInfoFile(ArrayList<String> commandOutput) throws IOException {
-        ArrayList<String> searchWords = new ArrayList<>(Arrays.asList(SEARCH_WORD));
+    protected ParseResult parseMemInfoFile(List<String> commandOutput) throws IOException {
+        List<String> searchWords = new ArrayList<>(Arrays.asList(SEARCH_WORD));
         ParseInstructions parseInstructions = new ParseInstructions(SEARCH_ELEMENT_INDEX, RETURN_ELEMENT_INDEX, REGEX_SPLIT, searchWords);
         ParseResult parseResult = OutputParser.parseSingleOutput(parseInstructions, commandOutput);
         if (!parseResult.getSearchWord().matches(SEARCH_WORD)) {
diff --git a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/NetRetriever.java b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/NetRetriever.java
index 746279915bf..f30d455f339 100644
--- a/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/NetRetriever.java
+++ b/node-maintainer/src/main/java/com/yahoo/vespa/hosted/node/verification/spec/retrievers/NetRetriever.java
@@ -11,11 +11,16 @@ import org.apache.commons.exec.ExecuteException;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
 /**
- * Created by olaa on 30/06/2017.
+ * Retrieves IPv4/IPv6 interface, and checks interface speed. If node should have IPv6, tries to ping6.
+ * The results are stored in a HardwareInfo instance
+ *
+ * @author olaaun
+ * @author sgrostad
  */
 public class NetRetriever implements HardwareRetriever {
 
@@ -48,8 +53,9 @@ public class NetRetriever implements HardwareRetriever {
         this.verifierSettings = verifierSettings;
     }
 
+    @Override
     public void updateInfo() {
-        ArrayList<ParseResult> parseResults = findInterface();
+        List<ParseResult> parseResults = findInterface();
         findInterfaceSpeed(parseResults);
         if (verifierSettings.isCheckIPv6()) {
             testPingResponse(parseResults);
@@ -57,10 +63,10 @@ public class NetRetriever implements HardwareRetriever {
         updateHardwareInfoWithNet(parseResults);
     }
 
-    protected ArrayList<ParseResult> findInterface() {
-        ArrayList<ParseResult> parseResults = new ArrayList<>();
+    protected List<ParseResult> findInterface() {
+        List<ParseResult> parseResults = new ArrayList<>();
         try {
-            ArrayList<String> commandOutput = commandExecutor.executeCommand(NET_FIND_INTERFACE);
+            List<String> commandOutput = commandExecutor.executeCommand(NET_FIND_INTERFACE);
             parseResults = parseNetInterface(commandOutput);
 
         } catch (IOException e) {
@@ -69,16 +75,16 @@ public class NetRetriever implements HardwareRetriever {
         return parseResults;
     }
 
-    protected ArrayList<ParseResult> parseNetInterface(ArrayList<String> commandOutput) {
-        ArrayList<String> searchWords = new ArrayList<>(Arrays.asList(SEARCH_WORD_INTERFACE_IP4, SEARCH_WORD_INTERFACE_IPV6));
+    protected List<ParseResult> parseNetInterface(List<String> commandOutput) {
+        List<String> searchWords = new ArrayList<>(Arrays.asList(SEARCH_WORD_INTERFACE_IP4, SEARCH_WORD_INTERFACE_IPV6));
         ParseInstructions parseInstructions = new ParseInstructions(INTERFACE_SEARCH_ELEMENT_INDEX, INTERFACE_RETURN_ELEMENT_INDEX, INTERFACE_NAME_REGEX_SPLIT, searchWords);
-        ArrayList<ParseResult> parseResults = OutputParser.parseOutput(parseInstructions, commandOutput);
+        List<ParseResult> parseResults = OutputParser.parseOutput(parseInstructions, commandOutput);
         return parseResults;
     }
 
-    protected void findInterfaceSpeed(ArrayList<ParseResult> parseResults) {
+    protected void findInterfaceSpeed(List<ParseResult> parseResults) {
         try {
-            ArrayList<String> commandOutput = commandExecutor.executeCommand(NET_CHECK_INTERFACE_SPEED);
+            List<String> commandOutput = commandExecutor.executeCommand(NET_CHECK_INTERFACE_SPEED);
             ParseResult parseResult = parseInterfaceSpeed(commandOutput);
             parseResults.add(parseResult);
         } catch (IOException e) {
@@ -86,8 +92,8 @@ public class NetRetriever implements HardwareRetriever {
         }
     }
 
-    protected ParseResult parseInterfaceSpeed(ArrayList<String> commandOutput) throws IOException {
-        ArrayList<String> searchWords = new ArrayList<>(Arrays.asList(SEARCH_WORD_INTERFACE_SPEED));
+    protected ParseResult parseInterfaceSpeed(List<String> commandOutput) throws IOException {
+        List<String> searchWords = new ArrayList<>(Arrays.asList(SEARCH_WORD_INTERFACE_SPEED));
         ParseInstructions parseInstructions = new ParseInstructions(INTERFACE_SPEED_SEARCH_ELEMENT_INDEX, INTERFACE_SPEED_RETURN_ELEMENT_INDEX, INTERFACE_SPEED_REGEX_SPLIT, searchWords);
         ParseResult parseResult = OutputParser.parseSingleOutput(parseInstructions, commandOutput);
         if (!parseResult.getSearchWord().matches(SEARCH_WORD_INTERFACE_SPEED)) {
@@ -96,9 +102,9 @@ public class NetRetriever implements HardwareRetriever {
         return parseResult;
     }
 
-    protected void testPingResponse(ArrayList<ParseResult> parseResults) {
+    protected void testPingResponse(List<ParseResult> parseResults) {
         try {
-            ArrayList<String> commandOutput = commandExecutor.executeCommand(PING_NET_COMMAND);
+            List<String> commandOutput = commandExecutor.executeCommand(PING_NET_COMMAND);
             parseResults.add(parsePingResponse(commandOutput));
         } catch (ExecuteException e) {
             logger.log(Level.WARNING, "Failed to execute ping6", e);
@@ -107,8 +113,8 @@ public class NetRetriever implements HardwareRetriever {
         }
     }
 
-    protected ParseResult parsePingResponse(ArrayList<String> commandOutput) throws IOException {
-        ArrayList<String> searchWords = new ArrayList<>(Arrays.asList(PING_SEARCH_WORD));
+    protected ParseResult parsePingResponse(List<String> commandOutput) throws IOException {
+        List<String> searchWords = new ArrayList<>(Arrays.asList(PING_SEARCH_WORD));
         ParseInstructions parseInstructions = new ParseInstructions(PING_SEARCH_ELEMENT_INDEX, PING_RETURN_ELEMENT_INDEX, PING_SPLIT_REGEX_STRING, searchWords);
         ParseResult parseResult = OutputParser.parseSingleOutput(parseInstructions, commandOutput);
         if (!parseResult.getSearchWord().matches(PING_SEARCH_WORD)) {
@@ -117,7 +123,7 @@ public class NetRetriever implements HardwareRetriever {
         return new ParseResult(PING_SEARCH_WORD, parseResult.getValue());
     }
 
-    protected void updateHardwareInfoWithNet(ArrayList<ParseResult> parseResults) {
+    protected void updateHardwareInfoWithNet(List<ParseResult> parseResults) {
         hardwareInfo.setIpv6Interface(false);
         hardwareInfo.setIpv4Interface(false);
         for (ParseResult parseResult : parseResults) {