Doesn't look like a performance problem - moving to Java in General (intermediate)...
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus
Joined: Jun 24, 2004
the realloc funtion changes the size of an allocated memory block: so it may be that your thread/application is bumping its head against the ceiling of heap memory allocated to the JVM by the OS.
You could always try specifying the maximum JVM heap size with the -Xmx flag and see what happens.