These are just notes I’ve made for myself while going thought the book “Head First Java”

Today’s Notes:

Source file Contains one Class, Class Contains one or more Methods, One method contains a set of statements.

Basic “Hello World” Program:

class HelloWorldApp {
   public static void main (String[] args) {
      System.out.println(“Hello World!”);
   }
}

NOTE the “S” in String[] is capitalized. Along with System, but I had gotten that one right. (Book uses a different example)

Must have a “main” method in every app, but not in every class.  Apps can contain multiple Class files.

Syntax:

• Statements end in Semicolon’s
• Most white spaces don’t matter
• Must declare type and name of variables (ie. int weight;)
• Classes and methods must be defined with in curly braces { }
• // Single Line Comments
• /* Multiline comments
      are like this with the Asterisk slashes */

while (condition) {
   statement;
}

for (initialization; termination; increment) {
    Statement;
}

One thing I can’t seem to remember the order of creation.

1. write / Save the .java file
2. Comple .java file : javac appfile.java This makes the .class file
3. Run the .class file: java appfile.