Java and the Command Line

1
Java and the Command Line

• Java PATH variable
• Compiling a program
• Basic Unix commands

2
Java PATH variable

• Install Java and find out the exact location of
  the jdk file
• C\Program Files\Java
• Dont need to do this if you have a Mac!
• Determine the version of Java installed
• jdk1.5.0_6
• jdk1.5.0_12
• jdk1.6.0
• Your PATH is
• C\Program Files\Java\ jdk1.5.0_12\bin

3
Java PATH variable (cont)

• You will need to set the PATH if you get an error
  saying something like javac is not a
  recognizable command
• The PATH is needed so you can invoke the Java
  compiler from any location (subdirectory) in your
  computer.
• Read corresponding document on how to change the
  PATH variable in your computer.
• Java Troubleshooting.pdf

4
Opening the Console Window

• Mac users
• open the TERMINAL application
• PC users
• go to START
• select PROGRAMS
• select ACCESSORIES
• select COMMAND PROMPT

5
Compiling a Java program

• From the command window (console) type
• javac filename.java
• This will compile your program creating the
  corresponding .class file. Or it will create
  error messages.
• The source file (example.java) and its
  corresponding class file (example.class) will be
  located in the same folder (subdirectory).

6
Executing a Java application

• From the command window (console) type
• java filename
• java filename.class
• You can compile several files at once
• javac file1.java file2.java file3.java
• Only one of those have a main() method
• Lets assume is file2
• Execute the application by typing
• java file2

7
Basic Unix commands

• ls displays the contents of the directory
  (folder)
• dir command in Windows
• rm filename deletes a file
• del filename command in Windows
• cd .. changes directories moving up one level
• cd moves to the home directory
• cd directory moves down to that directory

8
Readings

• Read the Java Troubleshooting.pdf document to set
  up the PATH variable.
• Read the Basic Unix Commands.pdf document.
• Section 1.1

9
Homework

• Lab 07 is this Monday the 12th