### Eclipse Workspace Patch 1.0
#P org.eclipse.jdt.core
diff --git model/org/eclipse/jdt/internal/core/DeltaProcessor.java model/org/eclipse/jdt/internal/core/DeltaProcessor.java
index c36e288..8accbb6 100644
--- model/org/eclipse/jdt/internal/core/DeltaProcessor.java
+++ model/org/eclipse/jdt/internal/core/DeltaProcessor.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2011 IBM Corporation and others.
+ * Copyright (c) 2000, 2013 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -998,7 +998,7 @@
 									// first remove the index so that it is forced to be re-indexed
 									this.manager.indexManager.removeIndex(entryPath);
 									// then index the jar
-									this.manager.indexManager.indexLibrary(entryPath, project.getProject(), ((ClasspathEntry)entries[j]).getLibraryIndexLocation());
+									this.manager.indexManager.indexLibrary(entryPath, project.getProject(), ((ClasspathEntry)entries[j]).getLibraryIndexLocation(), true);
 								} else {
 									URL indexLocation = ((ClasspathEntry)entries[j]).getLibraryIndexLocation();
 									if (indexLocation != null) { // force reindexing, this could be faster rather than maintaining the list
diff --git search/org/eclipse/jdt/internal/core/index/FileIndexLocation.java search/org/eclipse/jdt/internal/core/index/FileIndexLocation.java
index 67fc9ae..f0648dd 100644
--- search/org/eclipse/jdt/internal/core/index/FileIndexLocation.java
+++ search/org/eclipse/jdt/internal/core/index/FileIndexLocation.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2011 IBM Corporation and others.
+ * Copyright (c) 2011, 2013 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -38,6 +38,11 @@
 	}
 
 	public boolean createNewFile() throws IOException {
+		File directory = this.indexFile.getParentFile();
+		if (directory != null && !directory.exists()) {
+			directory.mkdirs();
+		}
+		// always call File#createNewFile() so that the IOException is thrown if there is a failure
 		return this.indexFile.createNewFile();
 	}
 
diff --git search/org/eclipse/jdt/internal/core/search/indexing/AddJarFileToIndex.java search/org/eclipse/jdt/internal/core/search/indexing/AddJarFileToIndex.java
index 46dfe21..42f0bb4 100644
--- search/org/eclipse/jdt/internal/core/search/indexing/AddJarFileToIndex.java
+++ search/org/eclipse/jdt/internal/core/search/indexing/AddJarFileToIndex.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2012 IBM Corporation and others.
+ * Copyright (c) 2000, 2013 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -44,16 +44,25 @@
 	IFile resource;
 	Scanner scanner;
 	private IndexLocation indexFileURL;
+	private final boolean forceIndexUpdate;
 
 	public AddJarFileToIndex(IFile resource, IndexLocation indexFile, IndexManager manager) {
+		this(resource, indexFile, manager, false);
+	}
+	public AddJarFileToIndex(IFile resource, IndexLocation indexFile, IndexManager manager, final boolean updateIndex) {
 		super(resource.getFullPath(), manager);
 		this.resource = resource;
 		this.indexFileURL = indexFile;
+		this.forceIndexUpdate = updateIndex;
 	}
 	public AddJarFileToIndex(IPath jarPath, IndexLocation indexFile, IndexManager manager) {
+		this(jarPath, indexFile, manager, false);
+	}
+	public AddJarFileToIndex(IPath jarPath, IndexLocation indexFile, IndexManager manager, final boolean updateIndex) {
 		// external JAR scenario - no resource
 		super(jarPath, manager);
 		this.indexFileURL = indexFile;
+		this.forceIndexUpdate = updateIndex;
 	}
 	public boolean equals(Object o) {
 		if (o instanceof AddJarFileToIndex) {
@@ -75,7 +84,7 @@
 
 		if (this.isCancelled || progressMonitor != null && progressMonitor.isCanceled()) return true;
 
-		if (this.indexFileURL != null) {
+		if (hasPreBuiltIndex()) {
 			boolean added = this.manager.addIndex(this.containerPath, this.indexFileURL);
 			if (added) return true;	
 			this.indexFileURL = null;
@@ -291,9 +300,21 @@
 		return false;
 	}
 	protected Integer updatedIndexState() {
-		return IndexManager.REBUILDING_STATE;
+
+		Integer updateState = null;
+		if(hasPreBuiltIndex()) {
+			updateState = IndexManager.REUSE_STATE;
+		}
+		else {
+			updateState = IndexManager.REBUILDING_STATE;
+		}
+		return updateState;
 	}
 	public String toString() {
 		return "indexing " + this.containerPath.toString(); //$NON-NLS-1$
 	}
-}
+
+	protected boolean hasPreBuiltIndex() {
+		return !this.forceIndexUpdate && (this.indexFileURL != null && this.indexFileURL.exists());
+	}
+}
\ No newline at end of file
diff --git search/org/eclipse/jdt/internal/core/search/indexing/IndexManager.java search/org/eclipse/jdt/internal/core/search/indexing/IndexManager.java
index d130e0f..4834c32 100644
--- search/org/eclipse/jdt/internal/core/search/indexing/IndexManager.java
+++ search/org/eclipse/jdt/internal/core/search/indexing/IndexManager.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2012 IBM Corporation and others.
+ * Copyright (c) 2000, 2013 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -67,10 +67,15 @@
 	private SimpleLookupTable participantsContainers = null;
 	private boolean participantUpdated = false;
 
+	// should JDT manage (update, delete as needed) pre-built indexes?
+	public static final String MANAGE_PRODUCT_INDEXES_PROPERTY = "jdt.core.manageProductIndexes"; //$NON-NLS-1$
+	private static final boolean IS_MANAGING_PRODUCT_INDEXES_PROPERTY = Boolean.getBoolean(MANAGE_PRODUCT_INDEXES_PROPERTY);
+
 	// Debug
 	public static boolean DEBUG = false;
 
-	public synchronized void aboutToUpdateIndex(IPath containerPath, Integer newIndexState) {
+
+public synchronized void aboutToUpdateIndex(IPath containerPath, Integer newIndexState) {
 	// newIndexState is either UPDATING_STATE or REBUILDING_STATE
 	// must tag the index as inconsistent, in case we exit before the update job is started
 	IndexLocation indexLocation = computeIndexLocation(containerPath);
@@ -136,6 +141,37 @@
 			removeIndexesState(locations);
 	}
 	deleteIndexFiles(knownPaths);
+}
+/**
+ * Compute the pre-built index location for a specified URL
+ */
+public synchronized IndexLocation computeIndexLocation(IPath containerPath, final URL newIndexURL) {
+	IndexLocation indexLocation = (IndexLocation) this.indexLocations.get(containerPath);
+	if (indexLocation == null) {
+		if(newIndexURL != null) {
+			indexLocation = IndexLocation.createIndexLocation(newIndexURL);
+			// update caches
+			indexLocation = (IndexLocation) getIndexStates().getKey(indexLocation);
+			this.indexLocations.put(containerPath, indexLocation);
+		}
+	}
+	else {
+		// an existing index location exists - make sure it has not changed (i.e. the URL has not changed)
+		URL existingURL = indexLocation.getUrl();
+		if (newIndexURL != null) {
+			// if either URL is different then the index location has been updated so rebuild.
+			if(!newIndexURL.equals(existingURL)) {
+				// URL has changed so remove the old index and create a new one
+				this.removeIndex(containerPath);
+				// create a new one
+				indexLocation = IndexLocation.createIndexLocation(newIndexURL);
+				// update caches
+				indexLocation = (IndexLocation) getIndexStates().getKey(indexLocation);
+				this.indexLocations.put(containerPath, indexLocation);
+			}
+		}
+	}
+	return indexLocation;
 }
 public synchronized IndexLocation computeIndexLocation(IPath containerPath) {
 	IndexLocation indexLocation = (IndexLocation) this.indexLocations.get(containerPath);
@@ -493,20 +529,33 @@
 	if (!isJobWaiting(request))
 		request(request);
 }
+public void indexLibrary(IPath path, IProject requestingProject, URL indexURL) {
+	this.indexLibrary(path, requestingProject, indexURL, false);
+}
+
 /**
  * Trigger addition of a library to an index
  * Note: the actual operation is performed in background
  */
-public void indexLibrary(IPath path, IProject requestingProject, URL indexURL) {
+public void indexLibrary(IPath path, IProject requestingProject, URL indexURL, final boolean updateIndex) {
 	// requestingProject is no longer used to cancel jobs but leave it here just in case
-	IndexLocation indexFile = indexURL != null ? IndexLocation.createIndexLocation(indexURL): null;
+	IndexLocation indexFile = null;
+	if(indexURL != null) {
+		if(IS_MANAGING_PRODUCT_INDEXES_PROPERTY) {
+			indexFile = computeIndexLocation(path, indexURL);
+		}
+		else {
+			indexFile = IndexLocation.createIndexLocation(indexURL);
+		}
+	}
 	if (JavaCore.getPlugin() == null) return;
 	IndexRequest request = null;
+	boolean forceIndexUpdate = IS_MANAGING_PRODUCT_INDEXES_PROPERTY && updateIndex;
 	Object target = JavaModel.getTarget(path, true);
 	if (target instanceof IFile) {
-		request = new AddJarFileToIndex((IFile) target, indexFile, this);
+		request = new AddJarFileToIndex((IFile) target, indexFile, this, forceIndexUpdate);
 	} else if (target instanceof File) {
-		request = new AddJarFileToIndex(path, indexFile, this);
+		request = new AddJarFileToIndex(path, indexFile, this, forceIndexUpdate);
 	} else if (target instanceof IContainer) {
 		request = new IndexBinaryFolder((IContainer) target, this);
 	} else {
@@ -675,6 +724,9 @@
 		indexFile.delete();
 	}
 	this.indexes.removeKey(indexLocation);
+	if (IS_MANAGING_PRODUCT_INDEXES_PROPERTY) {
+		this.indexLocations.removeKey(containerPath);
+	}
 	updateIndexState(indexLocation, null);
 }
 /**
@@ -1013,6 +1065,7 @@
 			else if (indexState == UPDATING_STATE) state = "UPDATING"; //$NON-NLS-1$
 			else if (indexState == UNKNOWN_STATE) state = "UNKNOWN"; //$NON-NLS-1$
 			else if (indexState == REBUILDING_STATE) state = "REBUILDING"; //$NON-NLS-1$
+			else if (indexState == REUSE_STATE) state = "REUSE"; //$NON-NLS-1$
 			Util.verbose("-> index state updated to: " + state + " for: "+indexLocation); //$NON-NLS-1$ //$NON-NLS-2$
 		}
 	}