title: Check whether database is empty
body: <p>I am trying to check if a sqlite database is empty using </p>
  
  <pre><code>public boolean chkDB(){
          boolean chk = false;
          Cursor mCursor = db.rawQuery("SELECT * FROM " + DATABASE_TABLE, null);
          if (mCursor != null){
              mCursor.moveToFirst();
              if (mCursor.getInt(0) == 0){
                  chk = false;
              }
          }else{
              chk = true;
          }
          return chk;
      }
  </code></pre>
  
  <p>but every time i call that method i get null pointer exception</p>
  
  <p><strong>My Logcat shows this</strong></p>
  
  <pre><code>06-28 22:35:19.519: E/AndroidRuntime(441):  at com.android.id.DBAdapter.chkDB(DBAdapter.java:82)
  06-28 22:58:06.269: E/AndroidRuntime(621): FATAL EXCEPTION: main
  06-28 22:58:06.269: E/AndroidRuntime(621): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.android.id/com.android.id.MainActivity}: java.lang.NullPointerException
  06-28 22:58:06.269: E/AndroidRuntime(621):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
  06-28 22:58:06.269: E/AndroidRuntime(621):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
  06-28 22:58:06.269: E/AndroidRuntime(621):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
  06-28 22:58:06.269: E/AndroidRuntime(621):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
  06-28 22:58:06.269: E/AndroidRuntime(621):  at android.os.Handler.dispatchMessage(Handler.java:99)
  06-28 22:58:06.269: E/AndroidRuntime(621):  at android.os.Looper.loop(Looper.java:123)
  06-28 22:58:06.269: E/AndroidRuntime(621):  at android.app.ActivityThread.main(ActivityThread.java:4627)
  06-28 22:58:06.269: E/AndroidRuntime(621):  at java.lang.reflect.Method.invokeNative(Native Method)
  06-28 22:58:06.269: E/AndroidRuntime(621):  at java.lang.reflect.Method.invoke(Method.java:521)
  06-28 22:58:06.269: E/AndroidRuntime(621):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
  06-28 22:58:06.269: E/AndroidRuntime(621):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
  06-28 22:58:06.269: E/AndroidRuntime(621):  at dalvik.system.NativeStart.main(Native Method)
  06-28 22:58:06.269: E/AndroidRuntime(621): Caused by: java.lang.NullPointerException
  06-28 22:58:06.269: E/AndroidRuntime(621):  at com.android.id.DBAdapter.chkDB(DBAdapter.java:82)
  06-28 22:58:06.269: E/AndroidRuntime(621):  at com.android.id.MainActivity.enterDB(MainActivity.java:66)
  06-28 22:58:06.269: E/AndroidRuntime(621):  at com.android.id.MainActivity.onCreate(MainActivity.java:23)
  06-28 22:58:06.269: E/AndroidRuntime(621):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
  06-28 22:58:06.269: E/AndroidRuntime(621):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
  06-28 22:58:06.269: E/AndroidRuntime(621):  ... 11 more
  </code></pre>