Simple App crashes when started, Android programming fault : A simple android program to Enter a text (in Edit text) and copy to clipboard (after hitting copy button)...

It crashes when opened, what am i missing?

    package com.quickclip.panky.quickclip;

    import android.content.ClipData;
    import android.content.ClipboardManager;
    import android.content.Context;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    import android.widget.EditText;
    
    public abstract class MainActivity extends AppCompatActivity implements View.OnClickListener {
    
        EditText e1;
        Button b1;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
            e1 = (EditText) findViewById(R.id.editText);
            b1 = (Button) findViewById(R.id.button);
    
            b1.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    copytext(view);
                }
            });
        }
    
            public void copytext(View view) {
            ClipboardManager clipboard = (ClipboardManager) getSystemService(Context.CLIPBOARD_SERVICE);
            ClipData clip = ClipData.newPlainText("Copied Text", (CharSequence) e1);
            clipboard.setPrimaryClip(clip);
            }
    
    }

I also tried using below with no success :

    ClipData clip = ClipData.newPlainText("Copied Text", String.valueOf(e1));