Java class sandbox with instrumentation support for online judges.

It implements:

• a much faster, unsynchronized ASCII-only System.out stream that's suitable for single-threaded online-judging scenarios
• support for disallowing particular classes from being loaded, to force certain solutions trivialized by the standard library
• optional unbuffering of standard output, for interactive problems without requiring users to flush manually
• logging of exceptional exits to a state file

To run a class Submission with agent the following suffices:

$ java -client -javaagent:/code/java-sandbox-agent.jar=[option, ...] Submission

Supported fields for the option list are:

• nobigmath — disables BigInteger and BigDecimal, raising appropriate exceptions if they are used
• unicode — encodes System.out as UTF-8 instead of ASCII, sacrificing performance for Unicode support
• nobuf — sets System.out as being line-buffered, for interactive problems
• unsafe — enables sun.misc.Unsafe, which is disabled by default