Why soot could not load classfile?

Question

In order to link the library with my application I trying to decompile the jar using soot, but got the error:

java -jar ./soot-2.5.0.jar -f dava -cp $JRE_HOME/lib/rt.jar:$JRE_HOME/lib/jce.jar:.  -process-dir ./library-jarfile.jar 
Soot started on Sun Oct 02 15:02:11 MSK 2016
Unknown tag in constant pool: 16 at entry 83
Exception in thread "main" java.lang.RuntimeException: Could not load classfile: java.util.concurrent.ConcurrentMap
        at soot.coffi.Util.resolveFromClassFile(Util.java:75)
        at soot.CoffiClassSource.resolve(CoffiClassSource.java:39)         

Why! Could you tell me?