Compile: g++ x.cpp
Run : ./a.out

Compile: javac -d bin -cp lib\* *.java
Run : java -cp bin\;lib\* org.junit.runner.JUnitCore EulerTest
Copy : cp tmp/pN.java p042.java
Clean : rm bin/*.class

• try using maven, gradle and ant
• make the prime generator a singleton, only generate primes once
• load larger inputs from files
• use streams and collectors more often, lazy evaluation