runtime error

    E/AndroidRuntime: FATAL EXCEPTION: main
                  Process: com.example.neacon.wijnendisplay, PID: 12063
                  java.lang.IllegalStateException: Could not execute method for android:onClick
                      at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
                      at android.view.View.performClick(View.java:5675)
                      at android.view.View$PerformClick.run(View.java:22641)
                      at android.os.Handler.handleCallback(Handler.java:836)
                      at android.os.Handler.dispatchMessage(Handler.java:103)
                      at android.os.Looper.loop(Looper.java:203)
                      at android.app.ActivityThread.main(ActivityThread.java:6251)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1063)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:924)
                   Caused by: java.lang.reflect.InvocationTargetException
                      at java.lang.reflect.Method.invoke(Native Method)
                      at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
                      at android.view.View.performClick(View.java:5675)
                      at android.view.View$PerformClick.run(View.java:22641)
                      at android.os.Handler.handleCallback(Handler.java:836)
                      at android.os.Handler.dispatchMessage(Handler.java:103)
                      at android.os.Looper.loop(Looper.java:203)
                      at android.app.ActivityThread.main(ActivityThread.java:6251)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1063)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:924)
                   Caused by: android.os.NetworkOnMainThreadException
                      at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1318)
                      at java.net.Inet6AddressImpl.lookupHostByName(Inet6AddressImpl.java:86)
                      at java.net.Inet6AddressImpl.lookupAllHostAddr(Inet6AddressImpl.java:74)
                      at java.net.InetAddress.getAllByName(InetAddress.java:757)
                      at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:147)
                      at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:169)
                      at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:124)
                      at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:366)
                      at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:601)
                      at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:520)
                      at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:498)
                      at com.example.neacon.wijnendisplay.Request.send(Request.java:40)
                      at com.example.neacon.wijnendisplay.MainActivity.btn_click(MainActivity.java:143)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
                      at android.view.View.performClick(View.java:5675)
                      at android.view.View$PerformClick.run(View.java:22641)
                      at android.os.Handler.handleCallback(Handler.java:836)
                      at android.os.Handler.dispatchMessage(Handler.java:103)
                      at android.os.Looper.loop(Looper.java:203)
                      at android.app.ActivityThread.main(ActivityThread.java:6251)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1063)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:924)
I/art: Enter while loop.
I/art: Enter while loop.
I/art: Enter while loop.