bootstrap class path not set in conjunction with -source 1.6

Question

I am upgrading my application from java 1.6 to 1.7. When I try to build using Maven 3.2.1, my build fails with below error msg:

[ERROR] Failed to execute goa         


        

Answer 1

I solved it using below configuration in my compiler plugin:

<fork>true</fork>
<executable>${JAVA_HOME}/bin/javac</executable>
<compilerVersion>1.7</compilerVersion>
<source>1.7</source>
<target>1.7</target>  

This will use the JDK which you have defined in your JAVA_HOME environment property.

Answer 2

Quote from this post:

Java 5.0 and 6 used to have poor support for compiling classes to target older versions of Java. It always supported the previous version, but often no more. Even if you could compile for previous version, you had to be careful not to use functionality which did exist in the previous versions.

You should either include -Xbootclasspath when using javac:

javac -Xbootclasspath:/path/to/jdk6/rt.jar -target 1.6 -source 1.6 Main.java

or compile using -target 1.7 (or higher of course):

javac -target 1.7 -source 1.7 Main.java

or use javac of jdk 6:

/path/to/jdk6/bin/javac Main.java