Remove redundant initializers

In most of these cases, the initializer is redundant because some other
assignment to the same location appears after the initialization but
before any use.

In a few cases involving fields, the explicit initialization value is
identical to what would be used implicitly.

cast/java/ecj/src/main/java/com/ibm/wala/cast/java/translator/jdt/JDTJava2CAstTranslator.java

@@ -186,7 +186,7 @@
 // possible)
 
 public abstract class JDTJava2CAstTranslator<T extends Position> {
-  protected boolean dump = false;
+  protected boolean dump;
 
   protected final CAst fFactory = new CAstImpl();
 
@@ -1083,7 +1083,7 @@ private ProcedureEntity(
       }
 
       if (fDecl != null) {
-        int i = 0; // index to start filling up with real params
+        int i; // index to start filling up with real params
         if ((fModifiers & Modifier.STATIC) != 0) {
           fParameterNames = new String[fDecl.parameters().size()];
           i = 0;

cast/java/src/main/java/com/ibm/wala/cast/java/translator/Java2IRTranslator.java

@@ -31,7 +31,7 @@ public class Java2IRTranslator {
 
   protected final SetOfClasses exclusions;
 
-  CAstRewriterFactory<?, ?> castRewriterFactory = null;
+  CAstRewriterFactory<?, ?> castRewriterFactory;
 
   public Java2IRTranslator(JavaSourceLoaderImpl srcLoader, SetOfClasses exclusions) {
     this(srcLoader, null, exclusions);

cast/js/nodejs/src/main/java/com/ibm/wala/cast/js/nodejs/NodejsRequiredSourceModule.java

@@ -70,7 +70,7 @@ public InputStream getInputStream() {
       Assertions.UNREACHABLE(e.getMessage());
     }
 
-    String wrapperSource = null;
+    final String wrapperSource;
     String ext = FilenameUtils.getExtension(getFile().toString()).toLowerCase();
     switch (ext) {
       case "js":

cast/js/src/main/java/com/ibm/wala/cast/js/callgraph/fieldbased/flowgraph/FlowGraph.java

@@ -185,8 +185,7 @@ public PointerAnalysis<ObjectVertex> getPointerAnalysis(
       private final Map<Pair<PrototypeField, ObjectVertex>, PrototypeFieldVertex> proto =
           HashMapFactory.make();
 
-      private GraphReachability<Vertex, ObjectVertex> pointerAnalysis =
-          computeClosure(graph, monitor, ObjectVertex.class);
+      final private GraphReachability<Vertex, ObjectVertex> pointerAnalysis;
 
       private final ExtensionGraph<Vertex> dataflow = new ExtensionGraph<>(graph);
 

cast/js/src/main/java/com/ibm/wala/cast/js/ipa/callgraph/correlations/extraction/CorrelatedPairExtractionPolicy.java

@@ -96,7 +96,7 @@ private boolean addCorrelation(
 
     if (!entity.getPosition().getURL().toString().equals(startPos.getURL().toString())) return true;
     Set<ChildPos> startNodes = findNodesAtPos(CAstNode.OBJECT_REF, startPos, entity);
-    Set<ChildPos> endNodes = null;
+    final Set<ChildPos> endNodes;
     if (corr instanceof ReadWriteCorrelation) {
       endNodes = findNodesAtPos(CAstNode.ASSIGN, endPos, entity);
     } else if (corr instanceof EscapeCorrelation) {
@@ -207,9 +207,9 @@ private static void filterNames(Set<ChildPos> nodes, String indexName) {
       String parmName,
       List<String> locals) {
     ChildPos pos = startNode;
-    CAstNode block = null;
-    int start = -1, end = 0;
-    int start_inner = -1, end_inner = -1;
+    CAstNode block;
+    int start, end;
+    int start_inner, end_inner = -1;
 
     do {
       if (pos != startNode && pos.getParentPos() instanceof ChildPos)

cast/js/src/testFixtures/java/com/ibm/wala/cast/js/test/CAstDumper.java

@@ -24,7 +24,6 @@
 import com.ibm.wala.util.collections.HashMapFactory;
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.Comparator;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -63,7 +62,7 @@ public String dump(CAstEntity entity) {
   }
 
   private void dump(CAstEntity entity, int indent, StringBuilder buf) {
-    Collection<CAstEntity> scopedEntities = Collections.emptySet();
+    final Collection<CAstEntity> scopedEntities;
     if (entity.getKind() == CAstEntity.SCRIPT_ENTITY) {
       buf.append(indent(indent)).append(entity.getName()).append(":\n");
       scopedEntities = dumpScopedEntities(entity, indent + 2, buf);

cast/js/src/testFixtures/java/com/ibm/wala/cast/js/test/TestForInBodyExtraction.java

@@ -53,8 +53,8 @@ public static String eraseGeneratedNames(String str) {
   }
 
   public void testRewriter(String testName, String in, String out) {
-    String expected = null;
-    String actual = null;
+    String expected;
+    String actual;
     try {
       final var tmp = File.createTempFile("test", ".js", tmpDir);
       FileUtil.writeFile(tmp, in);

cast/src/main/java/com/ibm/wala/cast/loader/CAstAbstractModuleLoader.java

@@ -162,9 +162,8 @@ private void translateModuleEntryToCAst(
       } else {
         TranslatorToCAst xlatorToCAst = getTranslatorToCAst(ast, moduleEntry, modules);
 
-        CAstEntity fileEntity = null;
         try {
-          fileEntity = xlatorToCAst.translateToCAst();
+          final CAstEntity fileEntity = xlatorToCAst.translateToCAst();
 
           if (DEBUG) {
             CAstPrinter.printTo(fileEntity, new PrintWriter(System.err));

cast/src/main/java/com/ibm/wala/cast/util/SourceBuffer.java

@@ -103,7 +103,7 @@ public SourceBuffer(Position p) throws IOException {
     try (Reader pr = p.getReader()) {
       try (BufferedReader reader = new BufferedReader(pr)) {
 
-        String currentLine = null;
+        String currentLine;
         List<String> lines = new ArrayList<>();
         int offset = 0, line = 0;
         do {
@@ -123,7 +123,7 @@ public SourceBuffer(Position p) throws IOException {
         int endColumn = -1;
         int startOffset = -1;
         int startLine = line;
-        int startColumn = -1;
+        final int startColumn;
         if (p.getLastOffset() >= 0) {
           if (p.getFirstOffset() == offset) {
             startOffset = p.getFirstOffset();

core/src/main/java/com/ibm/wala/analysis/arraybounds/hypergraph/weight/NormalOrder.java

@@ -13,7 +13,7 @@ public class NormalOrder implements Comparator<Weight> {
 
   @Override
   public int compare(Weight o1, Weight o2) {
-    int result = 0;
+    final int result;
 
     if (o1.getType() == Type.NOT_SET || o2.getType() == Type.NOT_SET) {
       throw new IllegalArgumentException("Tried to compare weights, which are not set yet.");

core/src/main/java/com/ibm/wala/analysis/arraybounds/hypergraph/weight/Weight.java

@@ -39,7 +39,7 @@ public Weight(Type type, int number) {
    * @return this + other
    */
   public Weight add(Weight other) {
-    Weight result = null;
+    final Weight result;
     if (this.getType() == Type.NUMBER) {
       if (other.getType() == Type.NUMBER) {
         result = new Weight(Type.NUMBER, this.getNumber() + other.getNumber());

core/src/main/java/com/ibm/wala/analysis/exceptionanalysis/ExceptionTransferFunctionProvider.java

@@ -71,7 +71,6 @@ public UnaryOperator<BitVectorVariable> getEdgeTransferFunction(CGNode dst, CGNo
      */
 
     Iterator<CallSiteReference> callsites = cg.getPossibleSites(src, dst);
-    BitVector filtered = new BitVector(transformer.getValues().getSize());
 
     if (callsites.hasNext()) {
 
@@ -84,7 +83,7 @@ public UnaryOperator<BitVectorVariable> getEdgeTransferFunction(CGNode dst, CGNo
         caught.retainAll(intraResult.getAnalysis(src).getCaughtExceptions(callsite));
       }
 
-      filtered = transformer.computeBitVector(caught);
+      BitVector filtered = transformer.computeBitVector(caught);
       return new BitVectorMinusVector(filtered);
     } else {
       // This case should not happen, as we should only get src, dst pairs,

core/src/main/java/com/ibm/wala/analysis/reflection/CloneInterpreter.java

@@ -162,7 +162,7 @@ private SSAInstruction[] makeStatements(IClass klass) {
     int retValue = nextLocal++;
     // value number of the result of the clone()
     NewSiteReference ref = NewSiteReference.make(NEW_PC, klass.getReference());
-    SSANewInstruction N = null;
+    final SSANewInstruction N;
     if (klass.isArrayClass()) {
       int length = nextLocal++;
       statements.add(insts.ArrayLengthInstruction(statements.size(), length, 1));

core/src/main/java/com/ibm/wala/analysis/reflection/FactoryBypassInterpreter.java

@@ -532,7 +532,7 @@ private void addStatementsForSetOfTypes(Iterator<IClass> it) {
         typesAllocated.add(T);
         int i = getLocalForType(T);
         NewSiteReference ref = NewSiteReference.make(getNewSiteForType(T), T);
-        SSANewInstruction a = null;
+        final SSANewInstruction a;
         if (T.isArrayType()) {
           int[] sizes = new int[((ArrayClass) klass).getDimensionality()];
           initValueNumberForConstantOne();

core/src/main/java/com/ibm/wala/analysis/reflection/ReflectiveInvocationInterpreter.java

@@ -175,7 +175,7 @@ private IR makeIR(IMethod method, IMethod target, Context recv) {
     // pointer
     int args[] = new int[nargs];
     int pc = 0;
-    int parametersVn = -1; // parametersVn will hold the value number of parameters array
+    final int parametersVn; // parametersVn will hold the value number of parameters array
 
     if (method.getReference().equals(CTOR_NEW_INSTANCE)) {
       // allocate the new object constructed
@@ -239,7 +239,7 @@ private IR makeIR(IMethod method, IMethod target, Context recv) {
     }
 
     int exceptions = nextLocal++;
-    int result = -1;
+    final int result;
 
     // emit the dispatch and return instructions
     if (method.getReference().equals(CTOR_NEW_INSTANCE)) {

core/src/main/java/com/ibm/wala/analysis/typeInference/TypeInference.java

@@ -646,7 +646,7 @@ private TypeAbstraction meetDeclaredExceptionTypes(SSAGetCaughtExceptionInstruct
       Iterator<TypeReference> it = bb.getCaughtExceptionTypes();
       TypeReference t = it.next();
       IClass klass = cha.lookupClass(t);
-      TypeAbstraction result = null;
+      TypeAbstraction result;
       if (klass == null) {
         // a type that cannot be loaded.
         // be pessimistic

core/src/main/java/com/ibm/wala/classLoader/BytecodeClass.java

@@ -211,7 +211,7 @@ public IField getField(Atom name) {
 
   @Override
   public IField getField(Atom name, TypeName type) {
-    boolean unresolved = false;
+    boolean unresolved;
     try {
       // typically, there will be at most one field with the name
       IField field = getField(name);
@@ -452,7 +452,7 @@ protected Collection<IClass> computeAllInterfacesAsCollection() {
 
     // at this point result holds all interfaces the class directly extends.
     // now expand to a fixed point.
-    Set<IClass> last = null;
+    Set<IClass> last;
     do {
       last = HashSetFactory.make(result);
       for (IClass i : last) {
@@ -519,7 +519,7 @@ protected void addFieldToList(
       Collection<Annotation> annotations,
       Collection<TypeAnnotation> typeAnnotations,
       TypeSignature sig) {
-    TypeName T = null;
+    final TypeName T;
     if (fieldType.get(fieldType.length() - 1) == ';') {
       T = TypeName.findOrCreate(fieldType, 0, fieldType.length() - 1);
     } else {

core/src/main/java/com/ibm/wala/classLoader/ClassLoaderImpl.java

@@ -291,7 +291,7 @@ private Map<String, Object> getAllClassAndSourceFileContents(
     Map<String, Object> result = HashMapFactory.make();
     try (final JarInputStream s =
         new JarInputStream(new ByteArrayInputStream(jarFileContents), false)) {
-      JarEntry entry = null;
+      JarEntry entry;
       while ((entry = s.getNextJarEntry()) != null) {
         byte[] entryBytes = getEntryBytes(entrySizesForFile.get(entry.getName()), s);
         if (entryBytes == null) {

core/src/main/java/com/ibm/wala/classLoader/ShrikeCTMethod.java

@@ -269,7 +269,7 @@ protected void processDebugInfo(BytecodeInfo bcInfo) throws InvalidClassFileExce
 
   @Override
   public String getLocalVariableName(int bcIndex, int localNumber) {
-    int[][] map = null;
+    final int[][] map;
     try {
       map = getBCInfo().localVariableMap;
     } catch (InvalidClassFileException e1) {

core/src/main/java/com/ibm/wala/classLoader/ShrikeIRFactory.java

@@ -46,7 +46,7 @@ public IR makeIR(final IBytecodeMethod<IInstruction> method, Context C, final SS
     if (method == null) {
       throw new IllegalArgumentException("null method");
     }
-    com.ibm.wala.shrike.shrikeBT.IInstruction[] shrikeInstructions = null;
+    final com.ibm.wala.shrike.shrikeBT.IInstruction[] shrikeInstructions;
     try {
       shrikeInstructions = method.getInstructions();
     } catch (InvalidClassFileException e) {

core/src/main/java/com/ibm/wala/core/util/shrike/ShrikeUtil.java

@@ -51,7 +51,7 @@ public static TypeReference makeTypeReference(ClassLoaderReference loader, Strin
       return p;
     }
     ImmutableByteArray b = ImmutableByteArray.make(type);
-    TypeName T = null;
+    final TypeName T;
     /*if (b.get(0) != '[') {
       T = TypeName.findOrCreate(b, 0, b.length() - 1);
     } else {*/

core/src/main/java/com/ibm/wala/core/util/strings/StringStuff.java

@@ -274,7 +274,7 @@ public static final TypeName[] parseForParameterNames(Language l, ImmutableByteA
             while (StringStuff.isTypeCodeChar(b, i)) {
               ++i;
             }
-            TypeName T = null;
+            final TypeName T;
             byte c = b.get(i++);
             if (c == TypeReference.ClassTypeCode || c == TypeReference.OtherPrimitiveTypeCode) {
               while (b.get(i++) != ';')

core/src/main/java/com/ibm/wala/dataflow/IFDS/TabulationSolver.java

@@ -550,7 +550,7 @@ protected void processCall(final PathEdge<T> edge) {
       if (DEBUG_LEVEL > 0) {
         System.err.println(" process return site: " + returnSite);
       }
-      IUnaryFlowFunction f = null;
+      final IUnaryFlowFunction f;
       if (hasCallee) {
         f = flowFunctionMap.getCallToReturnFlowFunction(edge.target, returnSite);
       } else {

core/src/main/java/com/ibm/wala/demandpa/alg/ContextSensitiveStateMachine.java

@@ -175,7 +175,7 @@ private void handleMethodEntry(CallerSiteContext callSite) {
           System.err.println("FOUND RECURSION");
           System.err.println("stack " + prevStack + " contains " + callSite);
         }
-        CallerSiteContext topCallSite = null;
+        CallerSiteContext topCallSite;
         CallStack tmpStack = prevStack;
         // mark the appropriate call sites as recursive
         // and pop them

core/src/main/java/com/ibm/wala/demandpa/alg/DemandRefinementPointsTo.java

@@ -330,12 +330,11 @@ private Pair<PointsToResult, Collection<InstanceKeyAndState>> outerRefinementLoo
       setNumNodesTraversed(0);
       setTraversalBudget(refinementPolicy.getBudgetForPass(passNum));
       Collection<InstanceKeyAndState> curP2Set = null;
-      PointsToComputer computer = null;
       boolean completedPassInBudget = false;
       try {
         while (true) {
           try {
-            computer = new PointsToComputer(queried);
+            final PointsToComputer computer = new PointsToComputer(queried);
             computer.compute();
             curP2Set = computer.getComputedP2Set(queried);
             // System.err.println("completed pass");
@@ -382,7 +381,7 @@ private Pair<PointsToResult, Collection<InstanceKeyAndState>> outerRefinementLoo
         break;
       }
     }
-    PointsToResult result = null;
+    final PointsToResult result;
     if (succeeded) {
       result = PointsToResult.SUCCESS;
     } else if (passNum == numPasses) {
@@ -491,7 +490,7 @@ public PointsToResult pointsToPassesPred(
         break;
       }
     }
-    PointsToResult result = null;
+    final PointsToResult result;
     if (succeeded) {
       result = PointsToResult.SUCCESS;
     } else if (passNum == numPasses) {
@@ -572,7 +571,7 @@ private Pair<PointsToResult, Collection<PointerKey>> getFlowsToInternal(
       setNumNodesTraversed(0);
       setTraversalBudget(refinementPolicy.getBudgetForPass(passNum));
       Collection<PointerKeyAndState> curFlowsToSet = null;
-      FlowsToComputer computer = null;
+      FlowsToComputer computer;
       try {
         while (true) {
           try {
@@ -619,7 +618,7 @@ private Pair<PointsToResult, Collection<PointerKey>> getFlowsToInternal(
         break;
       }
     }
-    PointsToResult result = null;
+    final PointsToResult result;
     if (succeeded) {
       result = PointsToResult.SUCCESS;
     } else if (passNum == numPasses) {
@@ -2433,7 +2432,7 @@ private Collection<Pair<PointerKey, PointerKey>> getBaseAndStored(
             return null;
           }
           IR ir = node.getIR();
-          PointerKey base = null, stored = null;
+          final PointerKey base, stored;
           if (field == ArrayContents.v()) {
             final SSAInstruction instruction =
                 ir.getInstructions()[fieldWrite.getInstructionIndex()];

core/src/main/java/com/ibm/wala/demandpa/flowgraph/AbstractDemandFlowGraph.java

@@ -346,7 +346,7 @@ private static void debugPrintIR(IR ir) {
 
   @Override
   public Set<CallerSiteContext> getPotentialCallers(PointerKey formalPk) {
-    CGNode callee = null;
+    final CGNode callee;
     if (formalPk instanceof LocalPointerKey) {
       callee = ((LocalPointerKey) formalPk).getNode();
     } else if (formalPk instanceof ReturnValueKey) {

core/src/main/java/com/ibm/wala/examples/drivers/PDFSlice.java

@@ -170,7 +170,7 @@ public static Process run(
       System.err.println("Statement: " + s);
 
       // compute the slice as a collection of statements
-      Collection<Statement> slice = null;
+      final Collection<Statement> slice;
       if (goBackward) {
         final PointerAnalysis<InstanceKey> pointerAnalysis = builder.getPointerAnalysis();
         slice = Slicer.computeBackwardSlice(s, cg, pointerAnalysis, dOptions, cOptions);

core/src/main/java/com/ibm/wala/ipa/callgraph/impl/AbstractRootMethod.java

@@ -149,7 +149,7 @@ public SSAAbstractInvokeInstruction addInvocation(int[] params, CallSiteReferenc
     CallSiteReference newSite =
         CallSiteReference.make(
             statements.size(), site.getDeclaredTarget(), site.getInvocationCode());
-    SSAAbstractInvokeInstruction s = null;
+    final SSAAbstractInvokeInstruction s;
     if (newSite.getDeclaredTarget().getReturnType().equals(TypeReference.Void)) {
       s = insts.InvokeInstruction(statements.size(), params, nextLocal++, newSite, null);
     } else {
@@ -238,7 +238,7 @@ private SSANewInstruction addAllocation(TypeReference T, boolean invokeCtor) {
           // allocate an instance for the array contents
           NewSiteReference n = NewSiteReference.make(statements.size(), e);
           int alloc = nextLocal++;
-          SSANewInstruction ni = null;
+          final SSANewInstruction ni;
           if (e.isArrayType()) {
             int[] sizes = new int[((ArrayClass) cha.lookupClass(T)).getDimensionality()];
             Arrays.fill(sizes, getValueNumberForIntConstant(1));

core/src/main/java/com/ibm/wala/ipa/callgraph/propagation/PropagationCallGraphBuilder.java

@@ -1331,7 +1331,7 @@ protected IntSet getInstanceKeysForClass(IClass klass) {
    */
   @SuppressWarnings("unused")
   protected IntSet filterForClass(IntSet S, IClass klass) {
-    MutableIntSet filter = null;
+    final MutableIntSet filter;
     if (klass.getReference().equals(TypeReference.JavaLangObject)) {
       return S;
     } else {