I run abc with the following command-line :

java -Xms512M -Xmx1G abc.main.Main 
-d "C:\sabs/local/system/temp/sablecc/sablecc" 
C:\sabs/local/benchmarks/sablecc/sablecc/*.java 
C:\sabs/local/benchmarks/sablecc/sablecc/analysis/*.java 
C:\sabs/local/benchmarks/sablecc/sablecc/node/*.java 
C:\sabs/local/benchmarks/sablecc/sablecc/lexer/*.java 
C:\sabs/local/benchmarks/sablecc/sablecc/parser/*.java

I get the following exception :

Exception in thread "main" polyglot.util.InternalCompilerError: unhandled exception during compilation
        at abc.main.Main.run(Main.java:628)
        at abc.main.Main.main(Main.java:198)
Caused by: java.lang.RuntimeException: Invalid type: null_type
        At soot.AbstractJasminClass$1.defaultCase(AbstractJasminClass.java:145)
        at soot.TypeSwitch.caseNullType(TypeSwitch.java:106)
        at soot.NullType.apply(NullType.java:63)
        at soot.AbstractJasminClass.jasminDescriptorOf(AbstractJasminClass.java:101)
        at soot.AbstractJasminClass.jasminDescriptorOf(AbstractJasminClass.java:187)
        at soot.AbstractJasminClass.emitMethod(AbstractJasminClass.java:643)
        at soot.AbstractJasminClass.<init>(AbstractJasminClass.java:565)
        at soot.baf.JasminClass.<init>(JasminClass.java:45)
        at soot.PackManager.writeClass(PackManager.java:645)
        at soot.PackManager.writeOutput(PackManager.java:390)
        at soot.PackManager.writeOutput(PackManager.java:342)
        at abc.main.Main.output(Main.java:1029)
        at abc.main.Main.run(Main.java:571)
        ... 1 more