I've been playing with generating our own reflection objects
rather than using the JDK classes.

My Javassist reflection methods are significantly faster

 int iterations = 10000000;

 public void testStressJavassist() throws Throwable
 {
 ClassInfo typeInfo = getClassInfo(String.class);
 MethodInfo methodInfo = typeInfo.getDeclaredMethod("toString", null);
 String hello = "Hello";
 long start = System.currentTimeMillis();
 for (int i = 0; i < iterations; ++i)
 methodInfo.invoke(hello, null);
 long end = System.currentTimeMillis();
 System.out.println("testStressJavassist " + (end - start) + "ms");
 }

 public void testStressReflect() throws Throwable
 {
 Method method = String.class.getDeclaredMethod("toString", null);
 String hello = "Hello";
 long start = System.currentTimeMillis();
 for (int i = 0; i < iterations; ++i)
 method.invoke(hello, null);
 long end = System.currentTimeMillis();
 System.out.println("testStressReflect " + (end - start) + "ms");
 }

 public void testStressJavassist2() throws Throwable
 {
 ClassInfo typeInfo = getClassInfo(String.class);
 TypeInfo intInfo = getTypeInfo(Integer.TYPE);
 MethodInfo methodInfo = typeInfo.getDeclaredMethod("charAt", new TypeInfo[] { intInfo });
 String hello = "Hello";
 Object[] params = { new Integer(4) };
 long start = System.currentTimeMillis();
 for (int i = 0; i < iterations; ++i)
 methodInfo.invoke(hello, params);
 long end = System.currentTimeMillis();
 System.out.println("testStressJavassist2 " + (end - start) + "ms");
 }

 public void testStressReflect2() throws Throwable
 {
 Method method = String.class.getDeclaredMethod("charAt", new Class[] { Integer.TYPE });
 String hello = "Hello";
 Object[] params = { new Integer(4) };
 long start = System.currentTimeMillis();
 for (int i = 0; i < iterations; ++i)
 method.invoke(hello, params);
 long end = System.currentTimeMillis();
 System.out.println("testStressReflect2 " + (end - start) + "ms");
 }

testStressJavassist 479ms
testStressReflect 2937ms
testStressJavassist2 1153ms
testStressReflect2 3344ms

java.lang.String.toString();

public Object invoke(Object target, Object[] args) throws Throwable {if (target == null) throw new IllegalArgumentException("Null target for
 toString()Ljava/lang/String;");if (target instanceof java.lang.String == false) throw new IllegalArgumentException("Target " + target + " i
s not an instance of java.lang.String for toString()Ljava/lang/String;");if (args != null && args.length != 0)throw new IllegalArgumentExcep
tion("Expected no parameters for toString()Ljava/lang/String;");return ((java.lang.String)target).toString();}

java.lang.String.charAt(int);

public Object invoke(Object target, Object[] args) throws Throwable {if (target == null) throw new IllegalArgumentException("Null target for
 charAt(I)C");if (target instanceof java.lang.String == false) throw new IllegalArgumentException("Target " + target + " is not an instance
of java.lang.String for charAt(I)C");if (args == null || args.length != 1) throw new IllegalArgumentException("Expected 1 parameter(s) for c
harAt(I)C");if (args[0] == null) throw new IllegalArgumentException("Parameter 0 cannot be null for int for charAt(I)C");if (args[0] != null
 && args[0] instanceof java.lang.Integer == false) throw new IllegalArgumentException("Parameter 0 is not an instance of java.lang.Integer f
or charAt(I)C");return new java.lang.Character(((java.lang.String)target).charAt(((java.lang.Integer)args[0]).intValue()));}

String.toString();

public Object invoke(Object target, Object[] args) throws Throwable {return ((java.lang.String)target).toString();}

String.charAt(int);

public Object invoke(Object target, Object[] args) throws Throwable {return new java.lang.Character(((java.lang.String)target).charAt(((java
.lang.Integer)args[0]).intValue()));}