app crash due to java.lang.IllegalStateException in android

I am not able to find the cause of this error in my code. Thank you in advance.

  java.lang.IllegalStateException: 
      at android.support.v4.app.FragmentManagerImpl.addFragment (FragmentManager.java:1679)
      at android.support.v4.app.BackStackRecord.executeOps (BackStackRecord.java:726)
      at android.support.v4.app.FragmentManagerImpl.executeOps (FragmentManager.java:2355)
      at android.support.v4.app.FragmentManagerImpl.executeOpsTogether (FragmentManager.java:2146)
      at android.support.v4.app.FragmentManagerImpl.optimizeAndExecuteOps (FragmentManager.java:2098)
      at android.support.v4.app.FragmentManagerImpl.execPendingActions (FragmentManager.java:2008)
      at android.support.v4.app.FragmentManagerImpl$1.run (FragmentManager.java:710)
      at android.os.Handler.handleCallback (Handler.java:751)
      at android.os.Handler.dispatchMessage (Handler.java:95)
      at android.os.Looper.loop (Looper.java:154)
      at android.app.ActivityThread.main (ActivityThread.java:6776)
      at java.lang.reflect.Method.invoke (Native Method)
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run (ZygoteInit.java:1496)
      at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:1386)