Craftbukkit: mvn clean install error

I am fairly new to UNIX and i am trying to use CraftBukkit to run my Minecraft Server.

This is what I did:

$ git clone git://github.com/Bukkit/CraftBukkit.git

$ cd CraftBukkit

$ mvn clean install

This is the error I get...

sam@qntm:~/CraftBukkit$ mvn clean install                                       
[INFO] Scanning for projects...                                                 
[INFO] ------------------------------------------------------------------------ 
[INFO] Building CraftBukkit                                                     
[INFO]    task-segment: [clean, install]                               开发者_JAVA百科         
[INFO] ------------------------------------------------------------------------ 
[INFO] [clean:clean]                                                            
[INFO] Deleting directory /home/sam/CraftBukkit/target                          
[INFO] [resources:resources]                                                    
[INFO] Using default encoding to copy filtered resources.                       
[INFO] [compiler:compile]                                                       
[INFO] Compiling 133 source files to /home/sam/CraftBukkit/target/classes       
[INFO] ------------------------------------------------------------------------ 
[ERROR] BUILD FAILURE                                                           
[INFO] ------------------------------------------------------------------------ 
[INFO] Compilation failure                                                      
Unable to locate the Javac Compiler in:                                         
/usr/lib/jvm/java-6-openjdk/jre/../lib/tools.jar                              
Please ensure you are using JDK 1.4 or above and           
not a JRE (the com.sun.tools.javac.Main class is required).                    
In most cases you can change the location of your Java                         
installation by setting the JAVA_HOME environment variable.                    


Unable to locate the Javac Compiler in:                                        
/usr/lib/jvm/java-6-openjdk/jre/../lib/tools.jar                             
Please ensure you are using JDK 1.4 or above and                               
not a JRE (the com.sun.tools.javac.Main class is required).                    
In most cases you can change the location of your Java                         
installation by setting the JAVA_HOME environment variable.                    

[INFO] ------------------------------------------------------------------------
[INFO] For more information, run Maven with the -e switch                      
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1 second                                                    
[INFO] Finished at: Tue Feb 08 17:42:57 MSK 2011                               
[INFO] Final Memory: 12M/151M                                                  
[INFO] ------------------------------------------------------------------------ 

Apologies if there is a really simple and obvious solution.

ensure that your JAVA-HOME variable is set to proper path. Here is described how to set it properly http://www.cyberciti.biz/faq/linux-unix-set-java_home-path-variable/