Fix Java compile issues under JDK 1.5

java/src/main/java/com/google/protobuf/ByteString.java

@@ -37,7 +37,6 @@ import java.io.OutputStream;
 import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.Iterator;
 import java.util.List;
@@ -776,6 +775,15 @@ public abstract class ByteString implements Iterable<Byte> {
       flushLastBuffer();
       return ByteString.copyFrom(flushedBuffers);
     }
+    
+    /**
+     * Implement java.util.Arrays.copyOf() for jdk 1.5.
+     */
+    private byte[] copyArray(byte[] buffer, int length) {
+      byte[] result = new byte[length];
+      System.arraycopy(buffer, 0, result, 0, Math.min(buffer.length, length));
+      return result;
+    }
 
     /**
      * Writes the complete contents of this byte array output stream to
@@ -800,7 +808,7 @@ public abstract class ByteString implements Iterable<Byte> {
         byteString.writeTo(out);
       }
 
-      out.write(Arrays.copyOf(cachedBuffer, cachedBufferPos));
+      out.write(copyArray(cachedBuffer, cachedBufferPos));
     }
 
     /**
@@ -853,7 +861,7 @@ public abstract class ByteString implements Iterable<Byte> {
     private void flushLastBuffer()  {
       if (bufferPos < buffer.length) {
         if (bufferPos > 0) {
-          byte[] bufferCopy = Arrays.copyOf(buffer, bufferPos);
+          byte[] bufferCopy = copyArray(buffer, bufferPos);
           flushedBuffers.add(new LiteralByteString(bufferCopy));
         }
         // We reuse this buffer for further writes.

java/src/main/java/com/google/protobuf/LazyField.java

@@ -157,12 +157,10 @@ class LazyField {
       this.entry = entry;
     }
 
-    @Override
     public K getKey() {
       return entry.getKey();
     }
 
-    @Override
     public Object getValue() {
       LazyField field = entry.getValue();
       if (field == null) {
@@ -175,7 +173,6 @@ class LazyField {
       return entry.getValue();
     }
 
-    @Override
     public Object setValue(Object value) {
       if (!(value instanceof MessageLite)) {
         throw new IllegalArgumentException(
@@ -193,13 +190,11 @@ class LazyField {
       this.iterator = iterator;
     }
 
-    @Override
     public boolean hasNext() {
       return iterator.hasNext();
     }
 
     @SuppressWarnings("unchecked")
-    @Override
     public Entry<K, Object> next() {
       Entry<K, ?> entry = iterator.next();
       if (entry.getValue() instanceof LazyField) {
@@ -208,7 +203,6 @@ class LazyField {
       return (Entry<K, Object>) entry;
     }
 
-    @Override
     public void remove() {
       iterator.remove();
     }

java/src/main/java/com/google/protobuf/LazyStringArrayList.java

@@ -172,7 +172,6 @@ public class LazyStringArrayList extends AbstractList<String>
     }
   }
 
-  @Override
   public List<?> getUnderlyingElements() {
     return Collections.unmodifiableList(list);
   }

java/src/main/java/com/google/protobuf/RopeByteString.java

@@ -36,13 +36,12 @@ import java.io.OutputStream;
 import java.io.UnsupportedEncodingException;
 import java.io.ByteArrayInputStream;
 import java.nio.ByteBuffer;
-import java.util.ArrayDeque;
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Deque;
 import java.util.Iterator;
 import java.util.List;
 import java.util.NoSuchElementException;
+import java.util.Stack;
 
 /**
  * Class to represent {@code ByteStrings} formed by concatenation of other
@@ -590,8 +589,7 @@ class RopeByteString extends ByteString {
     // Stack containing the part of the string, starting from the left, that
     // we've already traversed.  The final string should be the equivalent of
     // concatenating the strings on the stack from bottom to top.
-    private final Deque<ByteString> prefixesStack =
-        new ArrayDeque<ByteString>(minLengthByDepth.length);
+    private final Stack<ByteString> prefixesStack = new Stack<ByteString>();
 
     private ByteString balance(ByteString left, ByteString right) {
       doBalance(left);
@@ -703,8 +701,8 @@ class RopeByteString extends ByteString {
    */
   private static class PieceIterator implements Iterator<LiteralByteString> {
 
-    private final Deque<RopeByteString> breadCrumbs =
-        new ArrayDeque<RopeByteString>(minLengthByDepth.length);
+    private final Stack<RopeByteString> breadCrumbs =
+        new Stack<RopeByteString>();
     private LiteralByteString next;
 
     private PieceIterator(ByteString root) {

java/src/main/java/com/google/protobuf/UnmodifiableLazyStringList.java

@@ -145,7 +145,6 @@ public class UnmodifiableLazyStringList extends AbstractList<String>
     };
   }
 
-  @Override
   public List<?> getUnderlyingElements() {
     // The returned value is already unmodifiable.
     return list.getUnderlyingElements();