### Eclipse Workspace Patch 1.0
#P oak-core
Index: src/test/java/org/apache/jackrabbit/oak/plugins/document/RevisionVectorTest.java
===================================================================
--- src/test/java/org/apache/jackrabbit/oak/plugins/document/RevisionVectorTest.java	(revision 1746251)
+++ src/test/java/org/apache/jackrabbit/oak/plugins/document/RevisionVectorTest.java	(working copy)
@@ -382,4 +382,15 @@
         rv = rv.update(r12);
         assertEquals(new RevisionVector(br11, r12), rv.asBranchRevision(1));
     }
-}
+
+    @Test
+    public void fromString() throws Exception{
+        RevisionVector rv = new RevisionVector(
+                new Revision(1, 0, 1),
+                new Revision(2, 0, 2)
+        );
+
+        String rvstr = rv.asString();
+        RevisionVector rvFromStr = RevisionVector.fromString(rvstr);
+        assertEquals(rv, rvFromStr);
+    }}
Index: src/main/java/org/apache/jackrabbit/oak/plugins/document/RevisionVector.java
===================================================================
--- src/main/java/org/apache/jackrabbit/oak/plugins/document/RevisionVector.java	(revision 1746251)
+++ src/main/java/org/apache/jackrabbit/oak/plugins/document/RevisionVector.java	(working copy)
@@ -56,6 +56,8 @@
     private final static RevisionVector EMPTY = new RevisionVector();
 
     private final Revision[] revisions;
+    
+    private int hash;
 
     private RevisionVector(@Nonnull Revision[] revisions,
                            boolean checkUniqueClusterIds,
@@ -320,12 +322,16 @@
      * @return a string representation of this revision vector.
      */
     public String asString() {
-        StringBuilder sb = new StringBuilder();
-        String comma = "";
-        for (Revision r : revisions) {
-            sb.append(comma);
-            comma = ",";
-            r.toStringBuilder(sb);
+        int len = revisions.length;
+        if (len == 0) {
+            return "";
+        }
+        StringBuilder sb = new StringBuilder(len * Revision.REV_STRING_SIZE + len - 1);
+        for(int i=0; i<len; i++) {
+            if (i > 0) {
+                sb.append(',');
+            }
+            revisions[i].toStringBuilder(sb);
         }
         return sb.toString();
     }
@@ -339,8 +345,9 @@
      * @throws IllegalArgumentException if the string is malformed
      */
     public static RevisionVector fromString(String s) {
-        List<Revision> revisions = Lists.newArrayListWithCapacity(3);
-        for (String str : s.split(",")) {
+        String[] list = s.split(",");
+        List<Revision> revisions = Lists.newArrayListWithCapacity(list.length);
+        for (String str : list) {
             revisions.add(Revision.fromString(str));
         }
         return new RevisionVector(revisions);
@@ -446,17 +453,23 @@
     }
 
     @Override
-    public boolean equals(Object obj) {
-        if (obj instanceof RevisionVector) {
-            RevisionVector other = (RevisionVector) obj;
-            return Arrays.equals(revisions, other.revisions);
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
         }
-        return false;
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        RevisionVector other = (RevisionVector) o;
+        return Arrays.equals(revisions, other.revisions);
     }
 
     @Override
     public int hashCode() {
-        return Arrays.hashCode(revisions);
+        if (hash == 0){
+            hash = Arrays.hashCode(revisions);
+        }
+        return hash;
     }
 
     //-------------------------< internal >-------------------------------------