56: Highlights

• When you work with Java, you write source code, the Java compiler translates source code into byte code, and the Java virtual machine executes that byte code.
• Java programs consist of class definitions. If a program is to be a standalone program, one of the class definitions must contain a definition for a method named main. When you execute a standalone Java program, the Java virtual machine performs the computations specified in that main method.
• Java methods contain computation-specifying expressions embedded in statement sequences.
• Many expressions involve built-in operators, such as the addition operator, +. Operators do their work on operands.
• To test simple programs, you often use data that you supply when you write the program. Such data are said to be wired in.
• If you want to display data, then use a display statement:

  System.out.print(expression whose value is to be displayed); 
  

• If you want not only to display data, but also to terminate a line, then use println instead of print.