Executing a method from a APK/DEX

Load.java

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		TextView txtView = (TextView) findViewById(R.id.result);
		
		try {
			
			//Classes
			String className = "com.ufc.methods.Sum";
//			String paramclassName = "com.ufc.methods.Params";
			
			//Apk
			String appName = "StaticMath.apk";
			
			String pathExternalStorage = Environment.getExternalStorageDirectory().toString();
			File appDirectory =  new File(pathExternalStorage +"/" + appName);
						
			if(appDirectory.exists()){
				
				txtView.setText(appDirectory.toString());
				
				DexClassLoader dexLoader = new DexClassLoader(appDirectory.getAbsolutePath(), 
						getCacheDir().getAbsolutePath(), null, getClassLoader());
				
				Class sumClass = dexLoader.loadClass(className);
				Method executeMethod = sumClass.getMethods()[1];
				String result = "";
				
			try {
					try {
						executeMethod = sumClass.getMethod("execute", HashMap.class);
					} catch (NoSuchMethodException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}

				
				HashMap<String, String> hashMap = new HashMap<String, String>();
				hashMap.put("first", "33333");
				hashMap.put("second", "2");
			
	
					result = (String)executeMethod.invoke(this, hashMap);
				} catch (IllegalAccessException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				} catch (IllegalArgumentException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				} catch (InvocationTargetException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
					
				
					txtView.setText(result);				
			}
		}catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

Method executeMethod = sumClass.getMethods()[1];

OR

sumClass.getMethod("execute", HashMap.class);