Table of Contents
Java SE 7 Programmer I
This course is based on the exam topics for Java SE 7 Programmer I. You will get a solid Java programming base and preps you for the exam.
Basics
Define the scope of variables
Variables can hold all kinds of data. Java provides a way to limit access to them. These scope rules are as follows:
public: everyone
private: only this class
protected: only this class, this package, or subclass
static: globally without instance
final: cannot be changed or overridden
no modifier: only this class or this package
Scope is also limited to start and ending braces.
{ ... }
Define the structure of a Java class
- BasicClass.java
package nl.code4all.basics; class BasicClass { // fields/members/variables represent state int number; // methods/functions represent possible interaction void methodA() { } }
Create executable Java applications with a main method
- BasicApp.java
package nl.code4all.basics; public class BasicApp { // start point of application public static void main(String[] args) { System.out.println("Hi there"); } }
Import other Java packages
Create two new packages/folders nl.code4all.basics.a and nl.code4all.basics.b. Create two classes.
- ClassA.java
package nl.code4all.basics.a; public class ClassA { }
- ClassB.java
package nl.code4all.basics.b; import nl.code4all.basics.a.ClassA; public class ClassB { private void importFromOtherPackage() { ClassA a = new ClassA(); } }
Using the import nl.code4all.basics.a.ClassA; statement we can import and use code from another package.