Class<?> unsafeClass = Class.forName("sun.misc.Unsafe");
Field f = unsafeClass.getDeclaredField("theUnsafe");
f.setAccessible(true);
final Object unsafe = f.get(null);
final Method allocateInstance = unsafeClass.getMethod("allocateInstance", Class.class);
return new UnsafeAllocator() {
@Override
@SuppressWarnings("unchecked")
public <T> T newInstance(Class<T> c) throws Exception {
return (T) allocateInstance.invoke(unsafe, c);
}
};
} catch (Exception ignored) {
}
// try dalvikvm, pre-gingerbread
// public class ObjectInputStream {
// private static native Object newInstance(
// Class<?> instantiationClass, Class<?> constructorClass);
// }
try {
final Method newInstance = ObjectInputStream.class
.getDeclaredMethod("newInstance", Class.class, Class.class);
newInstance.setAccessible(true);
return new UnsafeAllocator() {
@Override
@SuppressWarnings("unchecked")
public <T> T newInstance(Class<T> c) throws Exception {
return (T) newInstance.invoke(null, c, Object.class);
}
};
} catch (Exception ignored) {
}
// try dalvikvm, post-gingerbread
// public class ObjectStreamClass {
// private static native int getConstructorId(Class<?> c);
// private static native Object newInstance(Class<?> instantiationClass, int methodId);
// }
try {
Method getConstructorId = ObjectStreamClass.class
.getDeclaredMethod("getConstructorId", Class.class);
getConstructorId.setAccessible(true);
final int constructorId = (Integer) getConstructorId.invoke(null, Object.class);
final Method newInstance = ObjectStreamClass.class
.getDeclaredMethod("newInstance", Class.class, int.class);
newInstance.setAccessible(true);
return new UnsafeAllocator() {
@Override
@SuppressWarnings("unchecked")
public <T> T newInstance(Class<T> c) throws Exception {
return (T) newInstance.invoke(null, c, constructorId);
}
};
} catch (Exception ignored) {
}
// give up
return new UnsafeAllocator() {
@Override
public <T> T newInstance(Class<T> c) {
throw new UnsupportedOperationException("Cannot allocate " + c);
}
};