I’m getting a force close on this activity due to a java.lang.nullpointerexception. It most

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Asked: June 11, 20262026-06-11T22:47:13+00:00 2026-06-11T22:47:13+00:00

I’m getting a force close on this activity due to a java.lang.nullpointerexception. It most

0

I’m getting a force close on this activity due to a java.lang.nullpointerexception.
It most likely has something to do with my SQLite DB commands, this is my first time working with them.

Here’s my code;

package com.example.gymbuddy;

import android.app.Activity;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.EditText;
import android.widget.TextView;

public class Benchmark extends Activity {

//Declaring Database and Table
private final String MY_DATABASE_NAME = "GymBuddy.db";
private final String MY_DATABASE_TABLE = "benchmark";
private static final int iVersion = 1;

//Defining Table
private static class TableClass {
private static final String BenchmarkData = "dataBenchmark";
private static final String COL_VAR = "variable";
private static final String COL_VAL = "value";
}

//To refer to the Database
private SQLiteDatabase db;


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_benchmark);

    db.execSQL(String.format("CREATE_TABLE %s(%s INTEGER PRIMARY KEY, %s TEXT)",
            TableClass.BenchmarkData, TableClass.COL_VAR, TableClass.COL_VAL));

}

public void onStart() {
    super.onStart();

    findViewById(R.id.button5).setOnClickListener(new handleButton5());

}

class handleButton5 implements OnClickListener {
    public void onClick(View v) {

        EditText editText1 = (EditText)findViewById(R.id.editText1);
        String sWeight = editText1.getText().toString();
        final double dWeight = Double.parseDouble(sWeight);

        EditText editText2 = (EditText)findViewById(R.id.editText2);
        String sPush = editText2.getText().toString();
        final double dPush = Double.parseDouble(sPush);

        EditText editText3 = (EditText)findViewById(R.id.editText3);
        String sSit = editText3.getText().toString();
        final double dSit = Double.parseDouble(sSit);

        EditText editText4 = (EditText)findViewById(R.id.editText4);
        String sPull = editText4.getText().toString();
        final double dPull = Double.parseDouble(sPull);

        double dBench = (((Math.floor(dWeight*.0664))*10)-10)+dPush;
        double dFlies = (Math.floor(((Math.floor(dBench*.6)/10)*10)));
        double dLats = ((Math.floor(dWeight*.05))*10)+dPull;
        double dCurls = ((Math.ceil(((dWeight*dPull)*.025)/10))*10);
        if(dCurls<20){
            dCurls = 20;
        }
        double dClose = ((Math.floor(dBench*.065))*10);
        double dRaise = 15;
        double dDcurls = Math.floor(dCurls*.4);
        double dDraise = 10;
        double dLegExt = dWeight*.5;
        double dPress = dWeight-20;
        double dSquat = (Math.floor((Math.floor(dWeight/10))*.6))*10;
        double dTricepExt = dDcurls+10;
        double dTricepKick = dDcurls;
        double dCalf = (Math.floor(dWeight*.035))*10;
        double dDead = (Math.floor(dWeight*.13))*10;

        int iBench = (int)dBench;
        int iFlies = (int)dFlies;
        int iLats = (int)dLats;
        int iCurls = (int)dCurls;
        int iClose = (int)dClose;
        int iRaise = (int)dRaise;
        int iDcurls = (int)dDcurls;
        int iDraise = (int)dDraise;
        int iLegExt = (int)dLegExt;
        int iPress = (int)dPress;
        int iSquat = (int)dSquat;
        int iTricepExt = (int)dTricepExt;
        int iTricepKick = (int)dTricepKick;
        int iCalf = (int)dCalf;
        int iDead = (int)dDead;
        int iSit = (int)dSit;

        TextView TextView1 = (TextView)findViewById(R.id.textView1);
        TextView1.setText(String.valueOf("Bench Press "+ iBench +" lbs"));

        TextView TextView2 = (TextView)findViewById(R.id.textView2);
        TextView2.setText(String.valueOf("Bar Curls "+ iCurls +" lbs"));

        TextView TextView3 = (TextView)findViewById(R.id.textView3);
        TextView3.setText(String.valueOf("Close Grip "+ iClose +" lbs"));

        TextView TextView4 = (TextView)findViewById(R.id.textView4);
        TextView4.setText(String.valueOf("Deltoid Raise "+ iRaise +" lbs"));

        TextView TextView5 = (TextView)findViewById(R.id.textView5);
        TextView5.setText(String.valueOf("Dumbbell Curls "+ iDcurls +" lbs"));

        TextView TextView6 = (TextView)findViewById(R.id.textView6);
        TextView6.setText(String.valueOf("Dumbbell Raise "+ iDraise +" lbs"));

        TextView TextView7 = (TextView)findViewById(R.id.textView7);
        TextView7.setText(String.valueOf("Lat Pull Down "+ iLats +" lbs"));

        TextView TextView8 = (TextView)findViewById(R.id.textView8);
        TextView8.setText(String.valueOf("Leg Extension "+ iLegExt +" lbs"));

        TextView TextView9 = (TextView)findViewById(R.id.textView9);
        TextView9.setText(String.valueOf("Leg Press "+ iPress +" lbs"));

        TextView TextView10 = (TextView)findViewById(R.id.textView10);
        TextView10.setText(String.valueOf("Pec Flies "+ iFlies +" lbs"));

        TextView TextView11 = (TextView)findViewById(R.id.textView11);
        TextView11.setText(String.valueOf("Squats "+ iSquat +" lbs"));

        TextView TextView12 = (TextView)findViewById(R.id.textView12);
        TextView12.setText(String.valueOf("Tricep Extension "+ iTricepExt +" lbs"));

        TextView TextView13 = (TextView)findViewById(R.id.textView13);
        TextView13.setText(String.valueOf("Tricep Kickbacks "+ iTricepKick +" lbs"));

        TextView TextView14 = (TextView)findViewById(R.id.textView14);
        TextView14.setText(String.valueOf("Calf Raises "+ iCalf));

        TextView TextView15 = (TextView)findViewById(R.id.textView15);
        TextView15.setText(String.valueOf("Dead Lift "+ iDead +" lbs"));

        TextView TextView16 = (TextView)findViewById(R.id.textView16);
        TextView16.setText(String.valueOf("Sit Ups "+ iSit));

        }
    }

}

Here’s my LogCat;

09-22 18:12:34.190: D/dalvikvm(540): Not late-enabling CheckJNI (already on)
09-22 18:12:35.649: D/dalvikvm(540): GC_FOR_ALLOC freed 77K, 3% free 9962K/10179K, paused 67ms
09-22 18:12:35.669: I/dalvikvm-heap(540): Grow heap (frag case) to 11.786MB for 2069904-byte allocation
09-22 18:12:35.779: D/dalvikvm(540): GC_CONCURRENT freed 1K, 3% free 11982K/12231K, paused 4ms+14ms
09-22 18:12:35.979: D/dalvikvm(540): GC_FOR_ALLOC freed <1K, 3% free 11983K/12231K, paused 39ms
09-22 18:12:36.010: I/dalvikvm-heap(540): Grow heap (frag case) to 13.685MB for 1991824-byte allocation
09-22 18:12:36.129: D/dalvikvm(540): GC_CONCURRENT freed <1K, 3% free 13928K/14215K, paused 5ms+26ms
09-22 18:12:36.439: D/gralloc_goldfish(540): Emulator without GPU emulation detected.
09-22 18:12:42.999: D/AndroidRuntime(540): Shutting down VM
09-22 18:12:43.010: W/dalvikvm(540): threadid=1: thread exiting with uncaught exception (group=0x409961f8)
09-22 18:12:43.029: E/AndroidRuntime(540): FATAL EXCEPTION: main
09-22 18:12:43.029: E/AndroidRuntime(540): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.gymbuddy/com.example.gymbuddy.Benchmark}: java.lang.NullPointerException
09-22 18:12:43.029: E/AndroidRuntime(540):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1955)
09-22 18:12:43.029: E/AndroidRuntime(540):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1980)
09-22 18:12:43.029: E/AndroidRuntime(540):  at android.app.ActivityThread.access$600(ActivityThread.java:122)
09-22 18:12:43.029: E/AndroidRuntime(540):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1146)
09-22 18:12:43.029: E/AndroidRuntime(540):  at android.os.Handler.dispatchMessage(Handler.java:99)
09-22 18:12:43.029: E/AndroidRuntime(540):  at android.os.Looper.loop(Looper.java:137)
09-22 18:12:43.029: E/AndroidRuntime(540):  at android.app.ActivityThread.main(ActivityThread.java:4340)
09-22 18:12:43.029: E/AndroidRuntime(540):  at java.lang.reflect.Method.invokeNative(Native Method)
09-22 18:12:43.029: E/AndroidRuntime(540):  at java.lang.reflect.Method.invoke(Method.java:511)
09-22 18:12:43.029: E/AndroidRuntime(540):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
09-22 18:12:43.029: E/AndroidRuntime(540):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
09-22 18:12:43.029: E/AndroidRuntime(540):  at dalvik.system.NativeStart.main(Native Method)
09-22 18:12:43.029: E/AndroidRuntime(540): Caused by: java.lang.NullPointerException
09-22 18:12:43.029: E/AndroidRuntime(540):  at com.example.gymbuddy.Benchmark.onCreate(Benchmark.java:34)
09-22 18:12:43.029: E/AndroidRuntime(540):  at android.app.Activity.performCreate(Activity.java:4465)
09-22 18:12:43.029: E/AndroidRuntime(540):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
09-22 18:12:43.029: E/AndroidRuntime(540):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1919)
09-22 18:12:43.029: E/AndroidRuntime(540):  ... 11 more

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1 Answer

Editorial Team · Answer 1 · 2026-06-11T22:47:15+00:00

So, problem is this:

db.execSQL([...]);

You call it but your database is not initialised so at first you need to init it:

Little snippet of code:

DataSource handler = new DataSource(this);
SQLiteDatabase db = handler.getWritableDatabase();

…next work with Cursors for example etc…

Your approach is so bad. Very good and clear approach is to use SQLiteOpenHelper, this class wraps everything what you need for your goal.

Here is simple example:

public class DataSource extends SQLiteOpenHelper {

    protected static final String DB_NAME = "BmiCalcHistoryDatabase";
    protected static final int START_DB_VERSION = 1;

    /* columns */
    protected static final String TABLE_NAME = "CalcHistory";
    protected static final String KEY_ID = "id";
    protected static final String KEY_RESULT = "result";
    protected static final String KEY_TYPE = "type";
    protected static final String KEY_DATE = "calcDate";

    public DataSource(Context cntx) {
        super(cntx, DB_NAME, null, START_DB_VERSION);
    }

    public void onCreate(SQLiteDatabase db) {
        String CREATE_QUERY = "CREATE TABLE " + TABLE_NAME + "("
                + KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
                + KEY_RESULT + " TEXT NOT NULL, "
                + KEY_TYPE + " TEXT NOT NULL, "
                + KEY_DATE + " TEXT NOT NULL" + ");";
        db.execSQL(CREATE_QUERY);
    }

    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        String DELETE_QUERY = "DROP TABLE IF EXISTS " + TABLE_NAME;
        db.execSQL(DELETE_QUERY);
        onCreate(db);
    }
}

You need to read some tutorial so check this:

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