Erro ao salvar dados na tabela do BD mysql

Connection conn = null;
			Statement stmt = null;
	
			final String JDBC_DRIVER = "com.mysql.jdbc.Driver";  
			final String DB_URL = "jdbc:mysql://localhost/public";

			final String USER = "root";
			final String PASS = "0124785369aA";

			Class.forName("com.mysql.jdbc.Driver");
 
			conn = DriverManager.getConnection(DB_URL,USER,PASS);
			stmt = conn.createStatement();
			
 			String sql = "insert into java" + " values (DEFAULT,?,?,?)";
			PreparedStatement stmt2 = conn.prepareStatement(sql);
			stmt2.setString(1, "bla");
			stmt2.setString(2, "bla2");
			stmt2.setString(3, "bla3");

			
			stmt2.execute();
			stmt2.close();
			conn.close();