use java 7 and 8 features

pitest-entry/src/main/java/org/pitest/mutationtest/ClassHistory.java

@@ -1,6 +1,7 @@
 package org.pitest.mutationtest;
 
 import java.io.Serializable;
+import java.util.Objects;
 
 import org.pitest.classinfo.ClassName;
 import org.pitest.classinfo.HierarchicalClassId;
@@ -31,41 +32,19 @@ public ClassName getName() {
 
   @Override
   public int hashCode() {
-    final int prime = 31;
-    int result = 1;
-    result = (prime * result)
-        + ((this.coverageId == null) ? 0 : this.coverageId.hashCode());
-    result = (prime * result) + ((this.id == null) ? 0 : this.id.hashCode());
-    return result;
+    return Objects.hash(id, coverageId);
   }
 
   @Override
   public boolean equals(final Object obj) {
     if (this == obj) {
       return true;
     }
-    if (obj == null) {
-      return false;
-    }
-    if (getClass() != obj.getClass()) {
+    if (obj == null || getClass() != obj.getClass()) {
       return false;
     }
     final ClassHistory other = (ClassHistory) obj;
-    if (this.coverageId == null) {
-      if (other.coverageId != null) {
-        return false;
-      }
-    } else if (!this.coverageId.equals(other.coverageId)) {
-      return false;
-    }
-    if (this.id == null) {
-      if (other.id != null) {
-        return false;
-      }
-    } else if (!this.id.equals(other.id)) {
-      return false;
-    }
-    return true;
+    return Objects.equals(id, other.id)
+            && Objects.equals(coverageId, other.coverageId);
   }
-
 }

pitest-entry/src/main/java/org/pitest/mutationtest/ClassMutationResults.java

@@ -2,6 +2,7 @@
 
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Objects;
 
 import org.pitest.classinfo.ClassName;
 
@@ -40,33 +41,19 @@ public String getPackageName() {
 
   @Override
   public int hashCode() {
-    final int prime = 31;
-    int result = 1;
-    result = (prime * result)
-        + ((this.mutations == null) ? 0 : this.mutations.hashCode());
-    return result;
+    return Objects.hash(mutations);
   }
 
   @Override
   public boolean equals(final Object obj) {
     if (this == obj) {
       return true;
     }
-    if (obj == null) {
-      return false;
-    }
-    if (getClass() != obj.getClass()) {
+    if (obj == null || getClass() != obj.getClass()) {
       return false;
     }
     final ClassMutationResults other = (ClassMutationResults) obj;
-    if (this.mutations == null) {
-      if (other.mutations != null) {
-        return false;
-      }
-    } else if (!this.mutations.equals(other.mutations)) {
-      return false;
-    }
-    return true;
+    return Objects.equals(mutations, other.mutations);
   }
 
   @Override

pitest-entry/src/main/java/org/pitest/mutationtest/MutationMetaData.java

@@ -16,9 +16,9 @@
 
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
+import java.util.Objects;
 
 import org.pitest.classinfo.ClassName;
 
@@ -35,7 +35,7 @@ public Collection<MutationResult> getMutations() {
   }
 
   public Collection<ClassMutationResults> toClassResults() {
-    Collections.sort(this.mutations, comparator());
+    this.mutations.sort(comparator());
     final List<ClassMutationResults> cmrs = new ArrayList<>();
     final List<MutationResult> buffer = new ArrayList<>();
     ClassName cn = null;
@@ -55,38 +55,23 @@ public Collection<ClassMutationResults> toClassResults() {
   }
 
   private static Comparator<MutationResult> comparator() {
-    return (arg0, arg1) -> arg0.getDetails().getId().compareTo(arg1.getDetails().getId());
+    return Comparator.comparing(arg0 -> arg0.getDetails().getId());
   }
 
   @Override
   public int hashCode() {
-    final int prime = 31;
-    int result = 1;
-    result = (prime * result)
-        + ((this.mutations == null) ? 0 : this.mutations.hashCode());
-    return result;
+    return Objects.hash(mutations);
   }
 
   @Override
   public boolean equals(final Object obj) {
     if (this == obj) {
       return true;
     }
-    if (obj == null) {
-      return false;
-    }
-    if (getClass() != obj.getClass()) {
+    if (obj == null || getClass() != obj.getClass()) {
       return false;
     }
     final MutationMetaData other = (MutationMetaData) obj;
-    if (this.mutations == null) {
-      if (other.mutations != null) {
-        return false;
-      }
-    } else if (!this.mutations.equals(other.mutations)) {
-      return false;
-    }
-    return true;
+    return Objects.equals(mutations, other.mutations);
   }
-
 }

pitest-entry/src/main/java/org/pitest/mutationtest/MutationResult.java

@@ -15,6 +15,7 @@
 package org.pitest.mutationtest;
 
 import java.util.List;
+import java.util.Objects;
 import java.util.Optional;
 import org.pitest.mutationtest.engine.MutationDetails;
 
@@ -67,42 +68,20 @@ public String getKillingTestDescription() {
 
   @Override
   public int hashCode() {
-    final int prime = 31;
-    int result = 1;
-    result = (prime * result)
-        + ((this.details == null) ? 0 : this.details.hashCode());
-    result = (prime * result)
-        + ((this.status == null) ? 0 : this.status.hashCode());
-    return result;
+    return Objects.hash(details, status);
   }
 
   @Override
   public boolean equals(final Object obj) {
     if (this == obj) {
       return true;
     }
-    if (obj == null) {
-      return false;
-    }
-    if (getClass() != obj.getClass()) {
+    if (obj == null || getClass() != obj.getClass()) {
       return false;
     }
     final MutationResult other = (MutationResult) obj;
-    if (this.details == null) {
-      if (other.details != null) {
-        return false;
-      }
-    } else if (!this.details.equals(other.details)) {
-      return false;
-    }
-    if (this.status == null) {
-      if (other.status != null) {
-        return false;
-      }
-    } else if (!this.status.equals(other.status)) {
-      return false;
-    }
-    return true;
+    return Objects.equals(details, other.details)
+            && Objects.equals(status, other.status);
   }
 
   @Override

pitest-entry/src/main/java/org/pitest/mutationtest/build/intercept/javafeatures/LineMutatorPair.java

@@ -1,5 +1,7 @@
 package org.pitest.mutationtest.build.intercept.javafeatures;
 
+import java.util.Objects;
+
 public class LineMutatorPair {
 
   private final int    lineNumber;
@@ -12,37 +14,19 @@ public LineMutatorPair(final int lineNumber, final String mutator) {
 
   @Override
   public int hashCode() {
-    final int prime = 31;
-    int result = 1;
-    result = (prime * result) + this.lineNumber;
-    result = (prime * result)
-        + ((this.mutator == null) ? 0 : this.mutator.hashCode());
-    return result;
+    return Objects.hash(lineNumber, mutator);
   }
 
   @Override
   public boolean equals(final Object obj) {
     if (this == obj) {
       return true;
     }
-    if (obj == null) {
-      return false;
-    }
-    if (getClass() != obj.getClass()) {
+    if (obj == null || getClass() != obj.getClass()) {
       return false;
     }
     final LineMutatorPair other = (LineMutatorPair) obj;
-    if (this.lineNumber != other.lineNumber) {
-      return false;
-    }
-    if (this.mutator == null) {
-      if (other.mutator != null) {
-        return false;
-      }
-    } else if (!this.mutator.equals(other.mutator)) {
-      return false;
-    }
-    return true;
+    return lineNumber == other.lineNumber
+            && Objects.equals(mutator, other.mutator);
   }
-
 }

pitest-entry/src/test/java/org/pitest/mutationtest/build/intercept/javafeatures/Loc.java

@@ -2,44 +2,32 @@
 
 import org.objectweb.asm.tree.AbstractInsnNode;
 
+import java.util.Objects;
+
 class Loc {
   int index;
   AbstractInsnNode node;
+
   @Override
   public String toString() {
     return "[" + this.index + "] " + this.node;
   }
+
   @Override
   public int hashCode() {
-    final int prime = 31;
-    int result = 1;
-    result = (prime * result) + this.index;
-    result = (prime * result) + ((this.node == null) ? 0 : this.node.hashCode());
-    return result;
+    return Objects.hash(index, node);
   }
+
   @Override
   public boolean equals(Object obj) {
     if (this == obj) {
       return true;
     }
-    if (obj == null) {
-      return false;
-    }
-    if (getClass() != obj.getClass()) {
+    if (obj == null || getClass() != obj.getClass()) {
       return false;
     }
     final Loc other = (Loc) obj;
-    if (this.index != other.index) {
-      return false;
-    }
-    if (this.node == null) {
-      if (other.node != null) {
-        return false;
-      }
-    } else if (!this.node.equals(other.node)) {
-      return false;
-    }
-    return true;
+    return index == other.index
+            && Objects.equals(node, other.node);
   }
-
 }

pitest-html-report/src/main/java/org/pitest/mutationtest/report/html/PackageSummaryData.java

@@ -1,10 +1,10 @@
 package org.pitest.mutationtest.report.html;
 
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 
 public class PackageSummaryData implements Comparable<PackageSummaryData> {
 
@@ -50,39 +50,25 @@ public String getPackageDirectory() {
   public List<MutationTestSummaryData> getSummaryData() {
     final ArrayList<MutationTestSummaryData> values = new ArrayList<>(
         this.fileNameToSummaryData.values());
-    Collections.sort(values, new MutationTestSummaryDataFileNameComparator());
+    values.sort(new MutationTestSummaryDataFileNameComparator());
     return values;
   }
 
   @Override
   public int hashCode() {
-    final int prime = 31;
-    int result = 1;
-    result = (prime * result)
-        + ((this.packageName == null) ? 0 : this.packageName.hashCode());
-    return result;
+    return Objects.hash(packageName);
   }
 
   @Override
   public boolean equals(final Object obj) {
     if (this == obj) {
       return true;
     }
-    if (obj == null) {
-      return false;
-    }
-    if (getClass() != obj.getClass()) {
+    if (obj == null || getClass() != obj.getClass()) {
       return false;
     }
     final PackageSummaryData other = (PackageSummaryData) obj;
-    if (this.packageName == null) {
-      if (other.packageName != null) {
-        return false;
-      }
-    } else if (!this.packageName.equals(other.packageName)) {
-      return false;
-    }
-    return true;
+    return Objects.equals(packageName, other.packageName);
   }
 
   @Override