by Alexandre Alapetite on 2007-09-30; updated 2008-05-15

Java batch compile

It is sometimes necessary to compile a Java project on a machine without any development tool.

I propose on this page a batch script (.bat) for Windows (MS-DOS style) able to locate the best Java version available on the machine and to use it to automatically compile a full Java project.

Script `.bat` for generic Java compilation

File structure

The Java project must follow a simple organisation:

.\JavaCompile.bat: The script presented on this page
.\src\: Folder containing Java sources (.java) of the project to compile
.\lib\: Optional folder for Java libraries (.jar) used by the project
.\bin\: Output folder where will automatically be placed the resulting compiled classes (.class)

Description

The script searches in the classic installation paths (such as C:\Program Files\Java\) for the best (most recent) version of Java available (since Java version 5, that is 1.5.0), with a priority for JDK on JRE.
The script builds a list of source files .java that are in .\src\.
The script builds a list of libraries .jar that are in .\lib\.
The script compiles the above with javac.exe into .\bin\

Script

This batch requires at least Windows 2000 (XP, Vista, ...).

JavaCompile.bat

@echo off
echo 	== Java batch compile by Alexandre Alapetite ==
echo 	== 2008-05-15  http://alexandre.alapetite.fr ==

rem Defines preferred Java path
rem set JAVA_HOME=C:\Program Files\Java\jdk1.6.0
if defined JAVA_HOME (
if exist "%JAVA_HOME%\bin\java.exe" goto foundJava
)
rem If the above path does not exist, try to find the latest Java
set JAVA_ROOT=%ProgramFiles%\Java\
if not exist "%JAVA_ROOT%\" set JAVA_ROOT=%SystemDrive%\Java\
if not exist "%JAVA_ROOT%\" set JAVA_ROOT=%HOMEDRIVE%\Java\
if not exist "%JAVA_ROOT%\" set JAVA_ROOT=%SystemDrive%\
echo Search Java JDK...
for /F "usebackq delims==" %%f in (`dir "%JAVA_ROOT%jdk*" /B /O:-N`) do if not exist "%JAVA_HOME%\bin\java.exe" (
set JAVA_HOME=%JAVA_ROOT%%%f
goto foundJava
)
echo Search Java JRE...
for /F "usebackq delims==" %%f in (`dir "%JAVA_ROOT%jre*" /B /O:-N`) do if not exist "%JAVA_HOME%\bin\java.exe" (
set JAVA_HOME=%JAVA_ROOT%%%f
goto foundJava
)
:foundJava
if exist "%JAVA_HOME%\bin\java.exe" goto okJava
echo Cannot find Java. Please instal Java or edit %%JAVA_HOME%% path.
goto end
:okJava
echo Java path "%JAVA_HOME%"
"%JAVA_HOME%\bin\java.exe" -version

rem Compile .\src\\*.java into .\bin\\*.class using libraries in .\lib\\*.jar
subst m: %0\..
rem "%0\.." is the real path of the batch file
pushd m:
cd \
echo Search java sources in .\src\...
dir src\*.java /B/S > javasrc.tmp~
if ERRORLEVEL 1 (
echo Cannot find Java source files in .\src\
goto abort
)
echo Search jar libraries in .\lib\...
if exist lib dir lib\*.jar /B/S > javalib.tmp~
echo Compile in .\bin\...
if exist bin rmdir /S /Q bin
mkdir bin
if exist lib (
echo on
@"%JAVA_HOME%\bin\javac.exe" -d bin -classpath @javalib.tmp~ @javasrc.tmp~
@echo off
) else (
echo on
@"%JAVA_HOME%\bin\javac.exe" -d bin @javasrc.tmp~
@echo off
)
echo Done.
:abort
del javasrc.tmp~
if exist lib del javalib.tmp~
popd
subst m: /d

:end
set JAVA_ROOT=
echo on