Notes for Java / javac users.

(I use Java as a better C++ and don't use any of the awt/swing stuff, so I can't help there, sorry---StuartYeates)

Makefile rules

make(1) and Java don't play very well together, because unless you're careful you end up starting a new VirtualMachine for every file you want to compile (see the 'classes' target below for a complete hack). Remember that tabs and spaces get confused when cutting and pasting (see MakeFile).

JAVAC=javac JAVACOPTIONS= -g:none -O

1. make a .class file from a .java file

%.class: %.java

$(JAVAC) $(JAVACOPTIONS) $<

1. JAVACC stuff
2. name/location of javacc executable

JAVACC=/home/say1/bin/javacc

1. javacc options

JAVACCOPTIONS=-SANITY_CHECK=true -FORCE_LA_CHECK=true -DEBUG_PARSER=true -DEBUG_TOKEN_MANAGER=true

1. build a java file from a JavaCC file

%.java: %.jj

$(JAVACC) $(JAVACCOPTIONS) $<

1. a target that builds all the .java files in sight

classes

$(JAVAC) $(JAVACOPTIONS) .java /.java //.java

Tool support

1. Javadoc is your friend.
2. Ant is your friend.
3. JavaDeps is your friend.

Errors

Sometimes javac/Java complains that it can't find files which are plainly there or complains that they're in the wrong place. This is almost always a classpath or a package interaction problem. If the file is not in a package and is in the current directory:

1. Check that the current directory is in the classpath
2. Check whether you need to specific !ClassName? or !ClassName?.java
3. Check spelling. Spelling matters.

If the file is in a package:

1. Check the above points
2. Check that the the file is in "/some/path/to/a/dircetory/some/package/heirarchy/!ClassName?.java" and is called "!ClassName?" and in "/some/package/heirarchy/" package
3. Check that "/some/path/to/a/dircetory/" is in the the classpath
4. Check that the current directory is not in the classpath
5. Check the package name again

UserSubmittedNotes