Getting to know your Java Programming Environment

Topics

• Java Program Development
• Build and run a Java program using IDE (NetBeans or Eclipse)
• Build and run a Java program using editor and JDK command line tools
• Differentiate between syntax-errors and runtime error

Java Program Development

The following figure describes the process of compiling and executing a Java program

Java Program Development Steps

Java Development Environment

• Option #1 – Use your editor of your choice for coding and then use command line Java tools from JDK such as “javac” (compiler) for compiling and “java” (Java runtime) for execution
• Option #2 – Use IDE (Integrated Development Environment)
  • NetBeans
  • Eclipse (for Eclipse-variant such as Spring Tool Suite, STS in short)
  • Intellij IDEA
• In general, IDE provides much more pleasant and productive development environment, so all Java developers use IDE of his/her choice for Java programming
  • For this course, you can use either NetBeans or Eclipse

Lab:

Exercise 0: Download and Install JDK and NetBeans or Eclipse/STS 1001_javase_progenv.zip

Build and run Java Program using Command-line Tools

Tools to Use

• Text Editor
  • Examples: Sublime Text, Textmate (Mac only), Notepad (Windows only), Vi or VIM, Emacs
• Java command line tools – are available /bin directory
  • javac – compiler, used for compilation
  • java – java runtime (java interpreter), used for execution

My First “Helloworld” Java Program

1 public class Hello {
2
3 /**
4 * My first Java program
5 */
6 public static void main( String[] args ){
7
8 //prints the string “Hello world” on screen
9 System.out.println(“Hello world”);
10
11 }
12 }

Use Text Editor & Command-line Tools

• Step 1: Using text editor, write Java program
  • Name it “Hello.java”
• Step 2: Compile the Java program
  • javac Hello.java
• Step 3: Run the Java program
  • java Hello

Lab:

Exercise 1: Build & Run Java Program using Text Editor and JDK Command-line Tools 1001_javase_progenv.zip

Build and run Java Program using IDE

What is IDE?

• Integrated Development Environment (IDE) provides complete application development environment
  • Code editor (with many conveniences such as syntax highlighting)
  • GUI builder (for building GUI application)
  • Built-in compiler 
  • Built-in debugger 
  • Built-in tester 
  • Built-in profiler (for performance measurement) 
  • Many more built-in features 
• Popular IDE's 
  • Eclipse or STS (Free), NetBeans (Free), IntelliJ IDEA (Free/Commercial)

Errors: Syntax Errors & Runtime Errors

Errors : Syntax (Compile) Errors

• Syntax Errors 
  • Errors are usually from typing errors 
  • Detected at compile time, hence the reason they are called compile errors 
• Common Syntax Errors: 
  • Misspelled a keyword in Java 
  • Forgot to write a semi-colon at the end of a statement

Example: Syntax Error

 Syntax Error detected by Compiler

Errors: Runtime Errors

Run-time Errors 

• Errors that will not display until you run your program 
• Examples:
  • You want your program to print 100 strings of “Hello world”, but it only printed 99. 
  • Your program expects a number input from the user, but the user inputted a string, and so your program causes an exception

Lab: Exercise 2: Build & Run Java Program using IDE 1001_javase_progenv.zip

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