Issue on generate apk file with ant tool in command prompt

Question

 I am able to generate signed apk file for android project using ant tool via command prompt.But i am not able to generate signed apk file to a android project when multiple dependency projects are there for that project.please help me to find a way to find solution for this.(with out using eclipse by using only command line)

[javac] (use -source 7 or higher to enable diamond operator)

[javac] D:\Work\Android WorkSpace\facebook\src\com\facebook\share\widget\Sha

reDialog.java:225: error: diamond operator is not supported in -source 1.5

[javac] ArrayList<ModeHandler> handlers = new ArrayList<>();

[javac] ^

[javac] (use -source 7 or higher to enable diamond operator)

[javac] 25 errors

[javac] 3 warnings

BUILD FAILED

D:\AndroidIDE\sdk\tools\ant\build.xml:597: The following error occurred while ex

ecuting this line:

D:\AndroidIDE\sdk\tools\ant\build.xml:716: The following error occurred while ex

ecuting this line:

D:\AndroidIDE\sdk\tools\ant\build.xml:730: Compile failed; see the compiler erro

r output for details.

Total time: 7 seconds