Cheat Sheet

Java Coding Standards

Program Structure

Every Java program is a class

Program execution begins with the main method (if it exists)

public class HelloWorld  {
 public static void main(String[] args) {
   System.out.println("Hello World!");
   System.out.println("Go PARTs!");
 }
}
public static void main(String[] args) {
  System.out.println("Hello World!");
  System.out.println("Go PARTs!");
}
System.out.println("Hello World!");
public class Foobar {
  public static void main(String[] args) {
    int totalScore = 0;
    System.out.println("Score" + totalScore);
  }
}

Objects

Classes

public class Hello {
  String myString = "";
  public Hello () {
    this.myString = "Default string";
  }
  public Hello (String myString) {
    this.myString = myString;
  }
  public String getMyString () {
    return myString;
  }
  public void printMyString () {
    System.out.println(myString);
  }
}

Member Variables

public class River {
  private String name;
  private int length;
  private int locks;
  ...
}

Constructor

public class River {
  ...
  public River(String inName, int inLen) {
    name = inName;
    length = inLen;
  }
  ...
}

Instantiating an Object

public class RiverTest {
  public static void main(String[] args) {
    River riverA;
    riverA = new River("Ohio",981);
    River riverB = new River("Kanawha",3000);
  }
}

riverA contains hash-code identifier of a particular River object, located somewhere in memory

Accessor Methods

public class River {
  private String name;
  private int length;
  …
  public String getName() {
    return name;
  }
}

Mutator Methods

public class River {
  private String name;
  private int length;
  …
  public void setName(String name) {
    this.name = name;
  }
}

Arrays

grades = new int[25];
String[] myNames = new String[42];

Revision #1
Created 24 April 2025 21:24:32 by Brandon Duke
Updated 24 April 2025 21:24:46 by Brandon Duke