Merge pull request #27 from Vrganj/patch-3

Allow use of interface

lxc/executors/java

@@ -1,6 +1,6 @@
 cd /tmp/$2
 cp code.code interim.java
-name=$(cat interim.java | grep -Eo 'public\s+class\s+([A-Za-z0-9]+)' | sed -n 's/  */ /gp' | cut -d' ' -f3)
+name=$(grep -Po "(?<=\n|\A)\s*(public\s+)?(class|interface)\s+\K([^\n\s{]+)" interim.java)
 mv interim.java $name.java
 timeout -s KILL 10 javac $name.java
 runuser runner$1 -c "cd /tmp/$2 ; cat args.args | xargs -d '\n' timeout -s KILL 3 java $name"