diff --git a/actors.ts b/actors.ts
index 32e2ecca..b5d19659 100644
--- a/actors.ts
+++ b/actors.ts
@@ -287,6 +287,7 @@ module J2ME {
     static createFromObject(object) {
       var classInfo = Object.create(ClassInfo.prototype, object);
       classInfo.resolved_constant_pool = new Array(classInfo.constant_pool.length);
+      classInfo.mangledName = mangleClass(classInfo);
       return classInfo;
     }
 
@@ -389,16 +390,6 @@ module J2ME {
     }
 
     private _mangleFields() {
-      if (false) {
-        // Safe mangling that includes className, fieldName and signature.
-        var fields = this.fields;
-        for (var j = 0; j < fields.length; j++) {
-          var fieldInfo = fields[j];
-          fieldInfo.mangledName = "$" + escapeString(fieldInfo.classInfo.className + "_" + fieldInfo.name + "_" + fieldInfo.signature);
-        }
-        return;
-      }
-
       // Keep track of how many times a field name was used and resolve conflicts by
       // prefixing filed names with numbers.
       var classInfo: ClassInfo;
@@ -546,11 +537,11 @@ module J2ME {
   }
 
   export class ArrayClassInfo extends ClassInfo {
-    constructor(className: string, elementClass?) {
+    constructor(className: string, elementClass: ClassInfo, mangledName?: string) {
       false && super(null);
       this.className = className;
       // TODO this may need to change for compiled code.
-      this.mangledName = className;
+      this.mangledName = mangledName;
       this.superClass = CLASSES.java_lang_Object;
       this.superClassName = "java/lang/Object";
       this.access_flags = 0;
@@ -589,22 +580,22 @@ module J2ME {
   PrimitiveClassInfo.prototype.interfaces = [];
 
   export class PrimitiveArrayClassInfo extends ArrayClassInfo {
-    constructor(className: string, elementClass?) {
-      super(className, elementClass);
+    constructor(className: string, elementClass: ClassInfo, mangledName: string) {
+      super(className, elementClass, mangledName);
     }
 
     get superClass() {
       return CLASSES.java_lang_Object;
     }
 
-    static Z = new PrimitiveArrayClassInfo("[Z", PrimitiveClassInfo.Z);
-    static C = new PrimitiveArrayClassInfo("[C", PrimitiveClassInfo.C);
-    static F = new PrimitiveArrayClassInfo("[F", PrimitiveClassInfo.F);
-    static D = new PrimitiveArrayClassInfo("[D", PrimitiveClassInfo.D);
-    static B = new PrimitiveArrayClassInfo("[B", PrimitiveClassInfo.B);
-    static S = new PrimitiveArrayClassInfo("[S", PrimitiveClassInfo.S);
-    static I = new PrimitiveArrayClassInfo("[I", PrimitiveClassInfo.I);
-    static J = new PrimitiveArrayClassInfo("[J", PrimitiveClassInfo.J);
+    static Z = new PrimitiveArrayClassInfo("[Z", PrimitiveClassInfo.Z, "Uint8Array");
+    static C = new PrimitiveArrayClassInfo("[C", PrimitiveClassInfo.C, "Uint16Array");
+    static F = new PrimitiveArrayClassInfo("[F", PrimitiveClassInfo.F, "Float32Array");
+    static D = new PrimitiveArrayClassInfo("[D", PrimitiveClassInfo.D, "Float64Array");
+    static B = new PrimitiveArrayClassInfo("[B", PrimitiveClassInfo.B, "Int8Array");
+    static S = new PrimitiveArrayClassInfo("[S", PrimitiveClassInfo.S, "Int16Array");
+    static I = new PrimitiveArrayClassInfo("[I", PrimitiveClassInfo.I, "Int32Array");
+    static J = new PrimitiveArrayClassInfo("[J", PrimitiveClassInfo.J, "Int64Array");
   }
 
   PrimitiveClassInfo.prototype.fields = [];
diff --git a/jit/baseline.ts b/jit/baseline.ts
index 7a7d187e..62fa0673 100644
--- a/jit/baseline.ts
+++ b/jit/baseline.ts
@@ -169,6 +169,17 @@ module J2ME {
     return "Long.fromInt(" + v + ")";
   }
 
+  function classConstant(classInfo: ClassInfo): string {
+    if (classInfo.mangledName) {
+      return classInfo.mangledName;
+    }
+    if (classInfo.isArrayClass) {
+      return "$AK(" + classConstant(classInfo.elementClass) + ")";
+    }
+    release || assert(classInfo.mangledName);
+    return classInfo.mangledName;
+  }
+
   export class BaselineCompiler {
     sp: number;
     pc: number;
@@ -308,7 +319,7 @@ module J2ME {
         if (classInfo.isInterface) {
           check = "$IOI";
         }
-        check += "(" + this.peek(Kind.Reference) + ", " +  mangleClass(classInfo) + ")";
+        check += "(" + this.peek(Kind.Reference) + ", " + classConstant(classInfo) + ")";
         check = " && " + check;
       }
       this.emitter.enter("if (pc >= " + handler.start_pc + " && pc < " + handler.end_pc + check + ") {");
@@ -591,11 +602,11 @@ module J2ME {
     }
 
     runtimeClass(classInfo: ClassInfo) {
-      return "$." + mangleClass(classInfo);
+      return "$." + classConstant(classInfo);
     }
 
     runtimeClassObject(classInfo: ClassInfo) {
-      return "$." + mangleClass(classInfo) + ".classObject";
+      return "$." + classConstant(classInfo) + ".classObject";
     }
 
     emitClassInitializationCheck(classInfo: ClassInfo) {
@@ -650,12 +661,12 @@ module J2ME {
         object = this.pop(Kind.Reference);
         if (opcode === Bytecodes.INVOKESPECIAL) {
           args.unshift(object);
-          call = mangleClassAndMethod(methodInfo) + ".call(" + args.join(", ") + ")";
+          call = methodInfo.mangledClassAndMethodName + ".call(" + args.join(", ") + ")";
         } else {
-          call = object + "." + mangleMethod(methodInfo) + "(" + args.join(", ") + ")";
+          call = object + "." + methodInfo.mangledName + "(" + args.join(", ") + ")";
         }
       } else {
-        call = mangleClassAndMethod(methodInfo) + "(" + args.join(", ") + ")";
+        call = methodInfo.mangledClassAndMethodName + "(" + args.join(", ") + ")";
       }
       if (methodInfo.implKey in inlineMethods) {
         emitDebugInfoComments && this.emitter.writeLn("// Inlining: " + methodInfo.implKey);
@@ -733,7 +744,7 @@ module J2ME {
     emitNewInstance(cpi: number) {
       var classInfo = this.lookupClass(cpi);
       this.emitClassInitializationCheck(classInfo);
-      this.emitPush(Kind.Reference, "new " + mangleClass(classInfo)+ "()");
+      this.emitPush(Kind.Reference, "new " + classConstant(classInfo)+ "()");
     }
 
     emitNewTypeArray(typeCode: number) {
@@ -749,7 +760,7 @@ module J2ME {
       if (classInfo.isInterface) {
         call = "$CCI";
       }
-      this.emitter.writeLn(call + "(" + object + ", " + mangleClass(classInfo) + ");");
+      this.emitter.writeLn(call + "(" + object + ", " + classConstant(classInfo) + ");");
     }
 
     emitInstanceOf(cpi: number) {
@@ -759,7 +770,7 @@ module J2ME {
       if (classInfo.isInterface) {
         call = "$IOI";
       }
-      this.emitPush(Kind.Int, call + "(" + object + ", " + mangleClass(classInfo) + ") | 0");
+      this.emitPush(Kind.Int, call + "(" + object + ", " + classConstant(classInfo) + ") | 0");
     }
 
     emitArrayLength() {
@@ -770,7 +781,7 @@ module J2ME {
       var classInfo = this.lookupClass(cpi);
       this.emitClassInitializationCheck(classInfo);
       var length = this.pop(Kind.Int);
-      this.emitPush(Kind.Reference, "$NA(" + mangleClass(classInfo) + ", " + length + ")");
+      this.emitPush(Kind.Reference, "$NA(" + classConstant(classInfo) + ", " + length + ")");
     }
 
     emitUnwind(pc: number, nextPC: number) {
diff --git a/jit/compiler.ts b/jit/compiler.ts
index c800af0f..a15d9f63 100644
--- a/jit/compiler.ts
+++ b/jit/compiler.ts
@@ -142,7 +142,7 @@ module J2ME {
 
   export function emitKlass(emitter: Emitter, classInfo: ClassInfo) {
     var writer = emitter.writer;
-    var mangledClassName = mangleClass(classInfo);
+    var mangledClassName = classInfo.mangledName;
     if (emitter.closure) {
       writer.writeLn("/** @constructor */");
     }
@@ -227,7 +227,7 @@ module J2ME {
       });
     }
 
-    var mangledClassName = mangleClass(classInfo);
+    var mangledClassName = classInfo.mangledName;
 
     emitter.writer.writeLn(mangledClassName + ".classSymbols = [" + referencedClasses.map(classInfo => {
       return quote(classInfo.className);
@@ -240,7 +240,7 @@ module J2ME {
                             methodFilter: (methodInfo: MethodInfo) => boolean,
                             ctx: Context): CompiledMethodInfo [] {
     var writer = emitter.writer;
-    var mangledClassName = mangleClass(classInfo);
+    var mangledClassName = classInfo.mangledName;
     if (!isIdentifierName(mangledClassName)) {
       mangledClassName = quote(mangledClassName);
     }
@@ -276,7 +276,7 @@ module J2ME {
       if (!methodFilter(method)) {
         continue;
       }
-      var mangledMethodName = mangleMethod(method);
+      var mangledMethodName = method.mangledName;
       if (!isIdentifierName(mangledMethodName)) {
         mangledMethodName = quote(mangledMethodName);
       }
@@ -285,7 +285,7 @@ module J2ME {
         continue;
       }
       try {
-        var mangledClassAndMethodName = mangleClassAndMethod(method);
+        var mangledClassAndMethodName = method.mangledClassAndMethodName;
         if (emitter.debugInfo) {
           writer.writeLn("// " + method.implKey + " (" + mangledClassAndMethodName + ") " + method.getSourceLocationForPC(0));
         }
diff --git a/runtime.ts b/runtime.ts
index 5c4e8cad..061ed44f 100644
--- a/runtime.ts
+++ b/runtime.ts
@@ -226,6 +226,8 @@ module J2ME {
   declare var util;
 
   import assert = J2ME.Debug.assert;
+  import concat3 = StringUtilities.concat3;
+  import concat5 = StringUtilities.concat5;
 
   export enum RuntimeStatus {
     New       = 1,
@@ -240,7 +242,10 @@ module J2ME {
     Compiled
   }
 
+  var hashMap = Object.create(null);
+
   var hashArray = new Int32Array(1024);
+
   function hashString(s: string) {
     if (hashArray.length < s.length) {
       hashArray = new Int32Array((hashArray.length * 2 / 3) | 0);
@@ -249,10 +254,18 @@ module J2ME {
     for (var i = 0; i < s.length; i++) {
       data[i] = s.charCodeAt(i);
     }
-    return HashUtilities.hashBytesTo32BitsAdler(data, 0, s.length);
-  }
+    var hash = HashUtilities.hashBytesTo32BitsMurmur(data, 0, s.length);
+
+    if (!release) { // Check to see that no collisions have ever happened.
+      if (hashMap[hash] && hashMap[hash] !== s) {
+        assert(false, "This is very bad.")
+      }
+      hashMap[hash] = s;
+    }
 
   var friendlyMangledNames = true;
+    return hash;
+  }
 
 
   function isIdentifierChar(c: number): boolean {
@@ -318,58 +331,55 @@ module J2ME {
   var stringHashes = Object.create(null);
   var stringHashCount = 0;
 
+  function hashStringStrong(s): string {
+    // Hash with Murmur hash.
+    var result = StringUtilities.variableLengthEncodeInt32(hashString(s));
+    // Also use the length for some more precision.
+    result += StringUtilities.toEncoding(s.length & 0x3f);
+    return result;
+  }
+
   export function hashStringToString(s: string) {
     if (stringHashCount > 1024) {
-      return StringUtilities.variableLengthEncodeInt32(hashString(s));
+      return hashStringStrong(s);
     }
     var c = stringHashes[s];
     if (c) {
       return c;
     }
-    c = stringHashes[s] = StringUtilities.variableLengthEncodeInt32(hashString(s));
+    c = stringHashes[s] = hashStringStrong(s);
     stringHashCount ++;
     return c;
   }
 
   export function mangleClassAndMethod(methodInfo: MethodInfo) {
-    var name = methodInfo.classInfo.className + "_" + methodInfo.name + "_" + hashStringToString(methodInfo.signature);
+    var name = concat5(methodInfo.classInfo.className, "_", methodInfo.name, "_", hashStringToString(methodInfo.signature));
     if (friendlyMangledNames) {
       return escapeString(name);
     }
-    var hash = hashString(name);
-    return StringUtilities.variableLengthEncodeInt32(hash);
+    return hashStringToString(name);
   }
 
   export function mangleMethod(methodInfo: MethodInfo) {
-    var name = methodInfo.name + "_" + hashStringToString(methodInfo.signature);
+    var name = concat3(methodInfo.name, "_", hashStringToString(methodInfo.signature));
     if (friendlyMangledNames) {
       return escapeString(name);
     }
-    var hash = hashString(name);
-    return StringUtilities.variableLengthEncodeInt32(hash);
+    return "$" + hashStringToString(name);
+  }
+
+  export function mangleClassName(name: string): string {
+    if (friendlyMangledNames) {
+      return "$" + escapeString(name);
+    }
+    return "$" + hashStringToString(name);
   }
 
   export function mangleClass(classInfo: ClassInfo) {
-    if (classInfo instanceof PrimitiveArrayClassInfo) {
-      switch (classInfo) {
-        case PrimitiveArrayClassInfo.Z: return "Uint8Array";
-        case PrimitiveArrayClassInfo.C: return "Uint16Array";
-        case PrimitiveArrayClassInfo.F: return "Float32Array";
-        case PrimitiveArrayClassInfo.D: return "Float64Array";
-        case PrimitiveArrayClassInfo.B: return "Int8Array";
-        case PrimitiveArrayClassInfo.S: return "Int16Array";
-        case PrimitiveArrayClassInfo.I: return "Int32Array";
-        case PrimitiveArrayClassInfo.J: return "Int64Array";
-      }
-    } else if (classInfo.isArrayClass) {
-      return "$AK(" + mangleClass(classInfo.elementClass) + ")";
-    } else {
-      if (friendlyMangledNames) {
-        return "$" + escapeString(classInfo.className);
-      }
-      var hash = hashString(classInfo.className);
-      return "$" + StringUtilities.variableLengthEncodeInt32(hash);
+    if (classInfo.mangledName) {
+      return classInfo.mangledName;
     }
+    return mangleClassName(classInfo.className);
   }
 
   /**
@@ -892,7 +902,7 @@ module J2ME {
 
   export function registerKlassSymbol(className: string) {
     // TODO: This needs to be kept in sync to how mangleClass works.
-    var mangledName = "$" + escapeString(className);
+    var mangledName = mangleClassName(className);
     if (RuntimeTemplate.prototype.hasOwnProperty(mangledName)) {
       return;
     }
@@ -1025,7 +1035,7 @@ module J2ME {
 
   function makeKlassConstructor(classInfo: ClassInfo): Klass {
     var klass: Klass;
-    var mangledName = mangleClass(classInfo);
+    var mangledName = classInfo.mangledName;
     if (classInfo.isInterface) {
       klass = <Klass><any>function () {
         Debug.unexpected("Should never be instantiated.")
@@ -1085,7 +1095,7 @@ module J2ME {
       return;
     }
     enterTimeline("linkKlass", {classInfo: classInfo});
-    var mangledName = mangleClass(classInfo);
+    var mangledName = classInfo.mangledName;
     var klass;
     classInfo.klass = klass = getKlass(classInfo);
     classInfo.klass.classInfo = classInfo;
@@ -1235,9 +1245,7 @@ module J2ME {
   }
 
   function findCompiledMethod(klass: Klass, methodInfo: MethodInfo): Function {
-    var name = methodInfo.mangledClassAndMethodName;
-    var method = jsGlobal[name];
-    return method;
+    return jsGlobal[methodInfo.mangledClassAndMethodName];
   }
 
   /**
@@ -1446,7 +1454,7 @@ module J2ME {
       return;
     }
 
-    var mangledClassAndMethodName = mangleClassAndMethod(methodInfo);
+    var mangledClassAndMethodName = methodInfo.mangledClassAndMethodName;
 
     compiledCount ++;
 
diff --git a/utilities.ts b/utilities.ts
index c4c6a402..e2b47092 100644
--- a/utilities.ts
+++ b/utilities.ts
@@ -965,6 +965,34 @@ module J2ME {
   }
 
   export module HashUtilities {
+    // https://github.com/garycourt/murmurhash-js
+    export function hashBytesTo32BitsMurmur(data: Uint8Array, offset: number, length: number) {
+      var l = length, h = 0x12345678 ^ l, i = offset, k;
+      while (l >= 4) {
+        k =
+          (data[i]) |
+          (data[++i] << 8) |
+          (data[++i] << 16) |
+          (data[++i] << 24);
+        k = (((k & 0xffff) * 0x5bd1e995) + ((((k >>> 16) * 0x5bd1e995) & 0xffff) << 16));
+        k ^= k >>> 24;
+        k = (((k & 0xffff) * 0x5bd1e995) + ((((k >>> 16) * 0x5bd1e995) & 0xffff) << 16));
+        h = (((h & 0xffff) * 0x5bd1e995) + ((((h >>> 16) * 0x5bd1e995) & 0xffff) << 16)) ^ k;
+        l -= 4;
+        ++i;
+      }
+      switch (l) {
+        case 3: h ^= data[i + 2] << 16;
+        case 2: h ^= data[i + 1] <<  8;
+        case 1: h ^= data[i];
+          h = (((h & 0xffff) * 0x5bd1e995) + ((((h >>> 16) * 0x5bd1e995) & 0xffff) << 16));
+      }
+      h ^= h >>> 13;
+      h = (((h & 0xffff) * 0x5bd1e995) + ((((h >>> 16) * 0x5bd1e995) & 0xffff) << 16));
+      h ^= h >>> 15;
+      return h >>> 0;
+    }
+
     export function hashBytesTo32BitsAdler(data: Uint8Array, offset: number, length: number): number {
       var a = 1;
       var b = 0;