erros showing in logcat
<pre><code>07-29 19:11:58.559: D/AndroidRuntime(306): Shutting down VM
07-29 19:11:58.569: W/dalvikvm(306): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
07-29 19:11:58.589: E/AndroidRuntime(306): FATAL EXCEPTION: main
07-29 19:11:58.589: E/AndroidRuntime(306): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.first.demo/com.first.demo.MainActivity}: java.lang.NullPointerException
07-29 19:11:58.589: E/AndroidRuntime(306):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
07-29 19:11:58.589: E/AndroidRuntime(306):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
07-29 19:11:58.589: E/AndroidRuntime(306):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
07-29 19:11:58.589: E/AndroidRuntime(306):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
07-29 19:11:58.589: E/AndroidRuntime(306):  at android.os.Handler.dispatchMessage(Handler.java:99)
07-29 19:11:58.589: E/AndroidRuntime(306):  at android.os.Looper.loop(Looper.java:123)
07-29 19:11:58.589: E/AndroidRuntime(306):  at android.app.ActivityThread.main(ActivityThread.java:4627)
07-29 19:11:58.589: E/AndroidRuntime(306):  at java.lang.reflect.Method.invokeNative(Native Method)
07-29 19:11:58.589: E/AndroidRuntime(306):  at java.lang.reflect.Method.invoke(Method.java:521)
07-29 19:11:58.589: E/AndroidRuntime(306):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
07-29 19:11:58.589: E/AndroidRuntime(306):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
07-29 19:11:58.589: E/AndroidRuntime(306):  at dalvik.system.NativeStart.main(Native Method)
07-29 19:11:58.589: E/AndroidRuntime(306): Caused by: java.lang.NullPointerException
07-29 19:11:58.589: E/AndroidRuntime(306):  at com.first.demo.MainActivity.onCreate(MainActivity.java:67)
07-29 19:11:58.589: E/AndroidRuntime(306):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
07-29 19:11:58.589: E/AndroidRuntime(306):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
07-29 19:11:58.589: E/AndroidRuntime(306):  ... 11 more
07-29 19:12:03.389: I/Process(306): Sending signal. PID: 306 SIG: 9
07-29 19:14:09.539: D/AndroidRuntime(319): Shutting down VM
07-29 19:14:09.539: W/dalvikvm(319): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
07-29 19:14:09.559: E/AndroidRuntime(319): FATAL EXCEPTION: main
07-29 19:14:09.559: E/AndroidRuntime(319): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.first.demo/com.first.demo.MainActivity}: java.lang.NullPointerException
07-29 19:14:09.559: E/AndroidRuntime(319):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
07-29 19:14:09.559: E/AndroidRuntime(319):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
07-29 19:14:09.559: E/AndroidRuntime(319):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
07-29 19:14:09.559: E/AndroidRuntime(319):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
07-29 19:14:09.559: E/AndroidRuntime(319):  at android.os.Handler.dispatchMessage(Handler.java:99)
07-29 19:14:09.559: E/AndroidRuntime(319):  at android.os.Looper.loop(Looper.java:123)
07-29 19:14:09.559: E/AndroidRuntime(319):  at android.app.ActivityThread.main(ActivityThread.java:4627)
07-29 19:14:09.559: E/AndroidRuntime(319):  at java.lang.reflect.Method.invokeNative(Native Method)
07-29 19:14:09.559: E/AndroidRuntime(319):  at java.lang.reflect.Method.invoke(Method.java:521)
07-29 19:14:09.559: E/AndroidRuntime(319):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
07-29 19:14:09.559: E/AndroidRuntime(319):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
07-29 19:14:09.559: E/AndroidRuntime(319):  at dalvik.system.NativeStart.main(Native Method)
07-29 19:14:09.559: E/AndroidRuntime(319): Caused by: java.lang.NullPointerException
07-29 19:14:09.559: E/AndroidRuntime(319):  at com.first.demo.MainActivity.onCreate(MainActivity.java:67)
07-29 19:14:09.559: E/AndroidRuntime(319):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
07-29 19:14:09.559: E/AndroidRuntime(319):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
07-29 19:14:09.559: E/AndroidRuntime(319):  ... 11 more
07-29 19:14:15.169: I/Process(319): Sending signal. PID: 319 SIG: 9
</code></pre>
