Issue using javax.script in Android programming

Question

I am new to Android programming, I'm trying to make a calculator for Android and I want to use javax.script, I have added the jar file library, I can import these:

import javax.script.ScriptEngineManager;
import javax.script.ScriptEngine;
import javax.script.ScriptException;

but when i declare this:

ScriptEngineManager mgr = new ScriptEngineManager();
ScriptEngine engine = mgr.getEngineByName("JavaScript");

my app just doesn't run. it shows "your app stops unfortunately". please let me know how can I use this for my app. Thank you in advance.

Errors in the logcat are:

02-04 00:58:06.179: E/AndroidRuntime(699): FATAL EXCEPTION: main
02-04 00:58:06.179: E/AndroidRuntime(699): java.lang.VerifyError: javax/script/ScriptEngineManager
02-04 00:58:06.179: E/AndroidRuntime(699):  at com.calculator.MainActivity$17.onClick(MainActivity.java:314)
02-04 00:58:06.179: E/AndroidRuntime(699):  at android.view.View.performClick(View.java:4084)
02-04 00:58:06.179: E/AndroidRuntime(699):  at android.view.View$PerformClick.run(View.java:16966)
02-04 00:58:06.179: E/AndroidRuntime(699):  at android.os.Handler.handleCallback(Handler.java:615)
02-04 00:58:06.179: E/AndroidRuntime(699):  at android.os.Handler.dispatchMessage(Handler.java:92)
02-04 00:58:06.179: E/AndroidRuntime(699):  at android.os.Looper.loop(Looper.java:137)
02-04 00:58:06.179: E/AndroidRuntime(699):  at android.app.ActivityThread.main(ActivityThread.java:4745)
02-04 00:58:06.179: E/AndroidRuntime(699):  at java.lang.reflect.Method.invokeNative(Native Method)
02-04 00:58:06.179: E/AndroidRuntime(699):  at java.lang.reflect.Method.invoke(Method.java:511)
02-04 00:58:06.179: E/AndroidRuntime(699):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
02-04 00:58:06.179: E/AndroidRuntime(699):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
02-04 00:58:06.179: E/AndroidRuntime(699):  at dalvik.system.NativeStart.main(Native Method)