Null pointer exception in shared preference

[raja-arumugam]

`
public static ChooseLaptopRepair chooselaptoprepair;
Button button;
RadioGroup radioGroup;
RadioButton radioButton1,radioButton2,radioButton3;
EditText issue;
Context context;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.choose_laptop_repair);

    getSupportActionBar().setDisplayHomeAsUpEnabled(true);

    radioGroup = (RadioGroup) findViewById(R.id.lapcondition);
    radioButton1 = (RadioButton) findViewById(R.id.laptopbattery);
    radioButton2 = (RadioButton) findViewById(R.id.laptopdisplay);
    radioButton3 = (RadioButton) findViewById(R.id.laptopOS);
    issue = (EditText) findViewById(R.id.laptopIssue);
    button= (Button) findViewById(R.id.laprepair);

    button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        Intent intent= new Intent(ChooseLaptopRepair.this,BranchActivityLaptopRepair.class);
        startActivity(intent);
        finish();
    }
});

    //error here
 saveRadioButton();
}

//error here
public void saveRadioButton() {
    SharedPreferences sharedPreferences = context.getSharedPreferences("chooselaptoprepair",MODE_PRIVATE);
    SharedPreferences.Editor shEditor = sharedPreferences.edit();
    shEditor.putBoolean("LapRepairButton1", radioButton1.isChecked()).apply();
    shEditor.putBoolean("LapRepairButton1", radioButton2.isChecked()).apply();
    shEditor.putBoolean("LapRepairButton1", radioButton3.isChecked()).apply();
    shEditor.commit();
}`