09-19 11:16:46.830: E/AndroidRuntime(1234): FATAL EXCEPTION: main
09-19 11:16:46.830: E/AndroidRuntime(1234): Process: com.project.attendancemanager, PID: 1234
09-19 11:16:46.830: E/AndroidRuntime(1234): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.project.attendancemanager/com.project.attendancemanager.TakeAttendance}: java.lang.NullPointerException
09-19 11:16:46.830: E/AndroidRuntime(1234):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
09-19 11:16:46.830: E/AndroidRuntime(1234):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
09-19 11:16:46.830: E/AndroidRuntime(1234):     at android.app.ActivityThread.access$800(ActivityThread.java:135)
09-19 11:16:46.830: E/AndroidRuntime(1234):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
09-19 11:16:46.830: E/AndroidRuntime(1234):     at android.os.Handler.dispatchMessage(Handler.java:102)
09-19 11:16:46.830: E/AndroidRuntime(1234):     at android.os.Looper.loop(Looper.java:136)
09-19 11:16:46.830: E/AndroidRuntime(1234):     at android.app.ActivityThread.main(ActivityThread.java:5017)
09-19 11:16:46.830: E/AndroidRuntime(1234):     at java.lang.reflect.Method.invokeNative(Native Method)
09-19 11:16:46.830: E/AndroidRuntime(1234):     at java.lang.reflect.Method.invoke(Method.java:515)
09-19 11:16:46.830: E/AndroidRuntime(1234):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
09-19 11:16:46.830: E/AndroidRuntime(1234):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
09-19 11:16:46.830: E/AndroidRuntime(1234):     at dalvik.system.NativeStart.main(Native Method)
09-19 11:16:46.830: E/AndroidRuntime(1234): Caused by: java.lang.NullPointerException
09-19 11:16:46.830: E/AndroidRuntime(1234):     at com.android.internal.os.LoggingPrintStream.println(LoggingPrintStream.java:298)
09-19 11:16:46.830: E/AndroidRuntime(1234):     at com.project.attendancemanager.DBHandler.getCourseData(DBHandler.java:129)
09-19 11:16:46.830: E/AndroidRuntime(1234):     at com.project.attendancemanager.TakeAttendance.loadCouSpinnerData(TakeAttendance.java:59)
09-19 11:16:46.830: E/AndroidRuntime(1234):     at com.project.attendancemanager.TakeAttendance.onCreate(TakeAttendance.java:38)
09-19 11:16:46.830: E/AndroidRuntime(1234):     at android.app.Activity.performCreate(Activity.java:5231)
09-19 11:16:46.830: E/AndroidRuntime(1234):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
09-19 11:16:46.830: E/AndroidRuntime(1234):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
09-19 11:16:46.830: E/AndroidRuntime(1234):     ... 11 more

package com.project.attendancemanager;


import java.util.List;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.Spinner;


public class TakeAttendance extends Activity implements OnItemSelectedListener{


    Button b;
    Spinner courseSp, classSp, subSp, timeSp;
    String selected;
    //DBHandler db;
    //int a;
    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_take_attendance);

        courseSp=(Spinner)findViewById(R.id.courseSpinner);
        classSp=(Spinner)findViewById(R.id.classSpinner);
        subSp=(Spinner)findViewById(R.id.subSpinner);
        timeSp=(Spinner)findViewById(R.id.timeSpinner);
        //b=(Button)findViewById(R.id.subBT);

        //db=new DBHandler(getApplicationContext());

        loadCouSpinnerData();
        courseSp.setOnItemSelectedListener(this);

    }
    //@Override
    public void onItemSelected(AdapterView<?> parent, View view, int position,
            long id) {
        // TODO Auto-generated method stub
        //selected=parent.getItemAtPosition(position).toString();
        //loadClassSpinnerData(selected);
    }

    @Override
    public void onNothingSelected(AdapterView<?> arg0) {
        // TODO Auto-generated method stub

    }

    private void loadCouSpinnerData() {
        // TODO Auto-generated method stub
        DBHandler db=new DBHandler(getApplicationContext());
        List<String> labels=db.getCourseData();
        ArrayAdapter<String> dataAdapter= new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item, labels);
        dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        courseSp.setAdapter(dataAdapter);
    }
    /*private void loadClassSpinnerData(String sel) {
        // TODO Auto-generated method stub
        //DBHandler db=new DBHandler(getApplicationContext());
        List<String> labels=db.getClassData(sel);
        ArrayAdapter<String> dataAdapter= new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item, labels);
        dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        classSp.setAdapter(dataAdapter);
    }*/
}

public List<String> getCourseData()
{
    List<String> data=new ArrayList<String>();
    String query="SELECT * FROM CourseTB";
    String  a = null;
    SQLiteDatabase db=this.getReadableDatabase();
    Cursor cursor=db.rawQuery(query, null);
    if(cursor.moveToFirst()){
        do{

            data.add(cursor.getString(1));
            a=cursor.getString(1);
        }while(cursor.moveToNext());
    }

    cursor.close();
    db.close();
    System.out.println(a);
    return data;
}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.project.attendancemanager"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="19" />
    <uses-permission android:name="android.permission.INTERNET"/>

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.project.attendancemanager.SplashScreen"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name="com.project.attendancemanager.Home"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="com.project.attendancemanager.HOME" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
        <activity
            android:name="com.project.attendancemanager.TakeAttendance"
            android:label="@string/app_name"
            android:parentActivityName="com.project.attendancemanager.Home" >
            <intent-filter>
                <action android:name="com.project.attendancemanager.TAKEATTENDANCE" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
        <activity
            android:name="com.project.attendancemanager.Eg"
            android:label="@string/title_activity_eg"
            android:parentActivityName="com.project.attendancemanager.TakeAttendance" >
            <intent-filter>
                <action android:name="com.project.attendancemanager.EG" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
        <activity
            android:name="com.project.attendancemanager.LoginActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="com.project.attendancemanager.LOGINACTIVITY" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
    </application>

</manifest>