How do I use Arduino ide-1.5.x from github?

billroy:
Here's what works for me:

Thanks a lot, I did not know about ant.
So this is a huge step forward.

'ant build' fails, why?

dada@i5:~$ git clone git://github.com/arduino/Arduino.git
Cloning into 'Arduino'...
remote: Counting objects: 39380, done.
remote: Compressing objects: 100% (12778/12778), done.
remote: Total 39380 (delta 23783), reused 37694 (delta 22893)
Receiving objects: 100% (39380/39380), 1.15 GiB | 477 KiB/s, done.
Resolving deltas: 100% (23783/23783), done.
dada@i5:~$ 
dada@i5:~$ cd Arduino/build/
dada@i5:~/Arduino/build$ ant clean
Unable to locate tools.jar. Expected to find it in /usr/lib/jvm/java-6-openjdk-amd64/lib/tools.jar
Buildfile: /home/dada/Arduino/build/build.xml

subprojects-clean:

clean:

clean:

linux-clean:

windows-clean:

macosx-clean:

clean:

BUILD SUCCESSFUL
Total time: 0 seconds
dada@i5:~/Arduino/build$ ant build
Unable to locate tools.jar. Expected to find it in /usr/lib/jvm/java-6-openjdk-amd64/lib/tools.jar
Buildfile: /home/dada/Arduino/build/build.xml

build:

revision-check:

linux-checkos:

subprojects-build:

compile:
  [methods] No changes to PApplet API.
    [mkdir] Created dir: /home/dada/Arduino/core/bin

BUILD FAILED
/home/dada/Arduino/build/build.xml:35: The following error occurred while executing this line:
/home/dada/Arduino/build/build.xml:67: The following error occurred while executing this line:
/home/dada/Arduino/core/build.xml:19: Unable to find a javac compiler;
com.sun.tools.javac.Main is not on the classpath.
Perhaps JAVA_HOME does not point to the JDK.
It is currently set to "/usr/lib/jvm/java-6-openjdk-amd64/jre"

Total time: 0 seconds
dada@i5:~/Arduino/build$