Object-Oriented Programming with Java Lecture Notes

29 January 2008 • Java Tools

Outline

Java environments. Documentation Java Tools. IDEs Analysis and testing.

The Java Environment

Java Components

Java Versions

• Use the -version option to find the installed version.

  $ java -version
  java version "1.6.0_03"
  Java(TM) SE Runtime Environment (build 1.6.0_03-b05)
  Java HotSpot(TM) Client VM (build 1.6.0_03-b05, mixed mode)
  
  $ javac -version
  javac 1.6.0_03
  
  $ 

• Relevant versions are:

  1.1 - Obsolete; stubborn web developers.
  1.5 (J2SE 5) - Course version (Core Java 7th ed).
  1.6 (J2SE 6) - Latest version (Core Java 8th ed).

Java Environments

• Java has four main environments:

  1. The server (J2EE); Enterprise edition.

  2. The desktop (J2SE); Standard edition.

  3. The browser; Plug-in part of J2SE.

  4. Portables (J2ME); Micro edition.

• This course uses the standard edition (and maybe the micro edition).

Documentation

• The Java system has extensive documentation.

• Available from Sun via the web or by download.

  • Download and install a local copy for fast access.

  • Alternate searches and printing too.

• You can also buy documentation (a.k.a. books).

  • They go out of date distressingly fast.

• Become adept with some form of documentation.

Documentation Types

• The two main documentation sets are for the class library APIs and the JDK.

  • Other documentation includes sample programs, tutorials, and white papers.

• The javadoc tool helps document class libraries in the Java style.

  • Any class library you use or create sould be documented.

IDEs

• An integrated development environment (IDE) is a hopped-up editor.

  

Java IDEs

• There's a fair number of Java IDEs.

  Eclipse
  NetBeans
  BlueJ
  DrJava
  Emacs + macros (JDEE, for example)

• There are others, including those you pay for.

DrJava

• DrJava is a simple IDE for Java.

  • BlueJ < DrJava < Eclipse.

• Available in the class directory

  /export/home/class/cs-310/drjava
  

• Run it with

  $ java -jar /export/home/class/cs-310/drjava/drjava-beta-20071221-0013.jar

Example.

Example..

Example...

Example....

Analysis and Testing

• Java analyzes and tests well.

  

FindBugs

• FindBugs is a static analyzer for errors and infelicities in Java code.

  • “Static” means the analyzed code isn't executed.

• Your assignments will be run through FindBugs.

• Available in the class directory

  /export/home/class/cs-310/findbugs-1.2.1
  

Example.

Example..

Example...

Example....

Example.....

Example......

FindBugs on the Cheap

• The Java compiler's -Xlint command-line option performs checks similar to FindBug's checks.

  • Similar to but not as detailed or as thorough.

  • On the other hand, what's it cost you?

Oh, One Last Thing

$ ls
AnonymousInnerClassTest.java  ForEachTest.java      StaticInnerClassTest.java
CloneTest.java                InnerClassTest2.java  TimerTest.java
EmployeeSortTest.java         InnerClassTest.java

$ findbugs -textui *.class
Exception in thread "main" java.io.IOException: IOException while scanning codebases
    at findbugs.FindBugs2.execute(FindBugs2.java:187)
    at findbugs.FindBugs.runMain(FindBugs.java:1521)
    at findbugs.FindBugs2.main(FindBugs2.java:731)
Caused by: findbugs.classfile.ResourceNotFoundException: Resource not found: 
    /home/rclayton/new-public-html/s08-310/code/java/chapter-6/*.class
    at findbugs.classfile.impl.SingleFileCodeBase.getClassDescriptor(SingleFileCodeBase.java:222)
    at findbugs.classfile.impl.SingleFileCodeBaseEntry.getClassDescriptor(SingleFileCodeBaseEntry.java:61)
    at findbugs.classfile.impl.ClassPathBuilder.build(ClassPathBuilder.java:229)
    at findbugs.FindBugs2.buildClassPath(FindBugs2.java:432)
    at findbugs.FindBugs2.execute(FindBugs2.java:160)
    ... 2 more

$ for i in *.java ; do javac $i ; done

$ findbugs -textui *.class
M B Eq: Employee defines compareTo(Employee) and uses Object.equals()  At EmployeeSortTest.java:[line 9]
Warnings generated: 1

$ 

• The cobbler's children have no shoes.

But Rather

$ ls
AnonymousInnerClassTest.java  ForEachTest.java      StaticInnerClassTest.java
CloneTest.java                InnerClassTest2.java  TimerTest.java
EmployeeSortTest.java         InnerClassTest.java

$ findbugs -textui *.class
Can't find *.class.

$ for i in *.java ; do javac $i ; done

$ findbugs -textui *.class
M B Eq: Employee defines compareTo(Employee) and uses Object.equals()  At EmployeeSortTest.java:[line 9]
Warnings generated: 1

$ 

JUnit

• JUnit is a unit-testing framework for Java.

• Unit tests are tests on small portions of a system.

  • In Java the unit's usually a class.

• Available in the class directory

  /export/home/class/cs-310/junit4.1
  

• When possible, assignments will have JUnit tests.

Example.

Example..

Example...

Example....

Example.....

Testing Tips

• Do it.

• Write lots of small, simple tests and run them all the time.

• Replicate every error as a test.

  • Learn thyself.

  • Make sure your fixes stay fixed.

• Develop code in measured steps and keep the tests up-to-date (and passing).

Summary

• Use the Java 5 or 6 Standard Environment (J2SE 5 or 6).

• Java is a relatively easy langugage to write tools for.

  • Avail yourself of them.

  • Maybe write a tool yourself.

• Learn how to use FindBugs and JUnit (and then use them).

References

• Using Static Analysis For Software Defect Detection by Bill Pugh, Google TechTalks, 2007 July 23.

Credits

• Stone Carving Tools At The Library Of Congress: Gear, Circular Saw Blade, Rasp, Hammers, Rifflers, Pointing Machine (Washington, DC) by takomabibelot, under an AT CC license.