Java exception hierarchy

 

Tips and examples:

Not recommended to catch type “Exception”, because catching the type Exception will catch all RuntimeException (like NullPointerException, ArrayIndexOutOfBoundsException) as well.

RuntimeException is unchecked exception, compile-time exception is checked exception.

Run time exceptons Example:

Base base = new Base();
Derive d = (Derive)base; // runtime exception: java.lang.ClassCastException
deal with ClassCastException:
way 1) catch (ClassCastException e)
way 2) if (base instanceof Derive)
                Derive d = (Derive)base;

Compile time exceptons Example:

    FileReader throws FileNotFoundException which extends IOException
    try {
        BufferedReader r = new BufferedReader(new FileReader("f"));
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }

    try {
        Connection conn = dataSource.getConnection();
        conn.createStatement().executeUpdate("insert into user values (null,'wjt276')");
        conn.close();
    } catch (SQLException e) {
        e.printStackTrace();

    }