Android Question Problem - use source 7 or higher

I have the following error on compile:

B4A version: 5.50
Parsing code. (0.00s)
Compiling code. (0.04s)
Compiling layouts code. (0.00s)
Generating R file. (0.72s)
Compiling debugger engine code. (0.66s)
Compiling generated Java code. Error
B4A line: 44
End Sub
javac 1.8.0_60
src\b4a\example\main.java:405: error: diamond operator is not supported in -source 1.5
private List<ShowEntity> scheduledShows = new ArrayList<>();
^
(use -source 7 or higher to enable diamond operator)
1 error

what is source 7?