Android : Need help understanding what exactly are the try-catch statements in java and android

I am a beginner developer and I am currently learning android and java etc.. I have the following lines of code and I am not exactly sure what the try-catch-finally statements are about. I understand that in the try part there is the sleep method which determines the length of the activity, but what about the rest please? Thanks in advance!

Thread timer = new Thread() {
        public void run() {
            try {
                sleep(5000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            } finally {
                Intent openStartingPoint = new Intent(
                        "com.example.testapp.MAINACTIVITY");
                startActivity(openStartingPoint);
            }
        }
    };
    timer.start();
}