[Demonstration 1]

[Buggy Method]
@Override
public void listAllMovies(Empty request, StreamObserver<MoviesInTheaterResponse> basicResponseObserver) {
    try {
        MoviesInTheaterResponse.Builder res = MoviesInTheaterResponse.newBuilder();
        for (Movie movie : movies) {
            res.addMovies(movie);
        }
        final ServerCallStreamObserver responseObserver = (ServerCallStreamObserver) basicResponseObserver;
        responseObserver.setOnReadyHandler(new Runnable() {

            @Override
            public void run() {
                while (responseObserver.isReady()) {
                    responseObserver.onNext(res.build());
                    responseObserver.onCompleted();
                }
            }
        });
    } catch (RuntimeException e) {
        logger.info(String.format("####### Runtime exception: {0} - {1} ", e.getMessage(), e.getStackTrace()));
    }
}

[Buggy Hunk]
logger.info(String.format("####### Runtime exception: {0} - {1} ", e.getMessage(), e.getStackTrace()));

[Patch]
logger.info(String.format("####### Runtime exception: {0} ", e.getMessage()));

[Demonstration 2]

[Buggy Method]
public void testSaveScoreGeneral() {
    ScoreAPI api = ScoreAPI.getInstance();
    try {
        Waldo waldo = new Waldo();
        waldo.setScore(1000);
        api.saveScore("Wyatt Smith", waldo.getScore());
        assertTrue(true);
    } catch (IOException exception) {
        LOGGER.info(ex);
        assertTrue(false);
    }
}

[Buggy Hunk]
LOGGER.info(ex);

[Patch]
LOGGER.log(Level.SEVERE, "Exception found", exception);

[Demonstration 3]

[Buggy Method]
private String buildUrl(Core core, String contextRoot, String serverUrl) {
    StringBuilder url = new StringBuilder(serverUrl);
    url.append(contextRoot).append(core.getName()).append(core.getPingHandler()).append("?wt=json");
    return url.toString();
}

[Buggy Hunk]
url.append(contextRoot).append(core.getName()).append(core.getPingHandler()).append("?wt=json");

[Patch]
url.append(contextRoot).append('/').append(core.getName()).append(core.getPingHandler()).append("?wt=json");