[Demonstration 1]

[Buggy Method]
@Test
public void itShouldThrowExceptionIfCeilingIsNegative() {
    try {
        getUnderTest().generatePrimeNumber(-10);
        fail("expecting exception here.");
    } catch (IllegalArgumentException ex) {
        assertEquals("ceiling cannot be -ve", ex.getMessage());
    }
}

[Buggy Hunk]
}catch (IllegalArgumentException ex){

[Patch]
}catch (InvalidParameterException ex){

[Demonstration 2]

[Buggy Method]
@Test
public void onCardFormSubmit_showsErrorsIfFormIsInvalid() {
    Configuration configuration = new TestConfigurationBuilder().challenges("cvv", "postal_code").buildConfiguration();
    mView.setup(mActivity, configuration);
    mView.onCardFormSubmit();
    assertEquals(RuntimeEnvironment.application.getString(R.string.bt_card_number_required), mView.getCardForm().getCardEditText().getTextInputLayoutParent().getError());
    assertEquals(RuntimeEnvironment.application.getString(R.string.bt_expiration_required), mView.getCardForm().getExpirationDateEditText().getTextInputLayoutParent().getError());
    assertEquals(RuntimeEnvironment.application.getString(R.string.bt_cvv_required), mView.getCardForm().getCvvEditText().getTextInputLayoutParent().getError());
    assertEquals(RuntimeEnvironment.application.getString(R.string.bt_postal_code_required), mView.getCardForm().getPostalCodeEditText().getTextInputLayoutParent().getError());
}

[Buggy Hunk]
assertEquals(RuntimeEnvironment.application.getString(R.string.bt_cvv_required),

[Patch]
assertEquals(RuntimeEnvironment.application.getString(R.string.bt_cvv_required, "CVV"),

[Demonstration 3]

[Buggy Method]
public void crawl() {
    try {
        Quota quota = twitter.TimelineQuota();
        // Exhaust the remaining limit
        for (long counter = 0; counter < quota.getLimit(); counter++) scheduler.next();
        // Wait until quota resets
        Thread.sleep(quota.getReset());
    } catch (InterruptedException ex) {
        // Recoverable error. Log and continue.
        logger.error(ex.getMessage(), ex);
    }
}

[Buggy Hunk]
logger.error(ex.getMessage(), ex);

[Patch]
logger.warn(ex.getMessage(), ex);