ant error: siamond operator is not supported

i try to build JLaTeXMath-android, which can be found here. However when i run ant i get

D:android studiojlatexmath-android-master>ant
Buildfile: D:android studiojlatexmath-android-masterbuild.xml

init:

compile:
    [javac] Compiling 147 source files to D:android studiojlatexmath-android-m
asterbin
    [javac] waing: [options] bootstrap class path not set in conjunction with
-source 1.5
    [javac] D:android studiojlatexmath-android-mastersrcorgscilabforgejla
texmathArrayOfAtoms.java:40: error: diamond operator is not supported in -sourc
e 1.5
    [javac]     array = new LinkedList<>();
    [javac]                            ^
    [javac]   (use -source 7 or higher to enable diamond operator)
    [javac] D:android studiojlatexmath-android-mastersrcorgscilabforgejla
texmathBox.java:106: error: diamond operator is not supported in -source 1.5
    [javac]     protected LinkedList<Box> children = new LinkedList<>();
    [javac]                                                         ^
    [javac]   (use -source 7 or higher to enable diamond operator)
    [javac] 2 errors
    [javac] 1 waing

BUILD FAILED
D:android studiojlatexmath-android-masterbuild.xml:88: Compile failed; see th
e compiler error output for details.

Total time: 0 seconds

I also tried ant -Djava.source=7 -Djava.target=7 with the same result. any ideas?