Jconsole is a JMX-compliant monitoring tool. It uses the extensive JMX instrumentation of the Java virtual machine to provide information on performance and resource consumption of applications running on the Java platform.
X-develop, and its little brother CodeGuide, are commercial IDEs that are developed by Omnicore and respectively sell for $499 and $399. CodeGuide includes Java support, while X-develop also supports C# and Visual Basic on .NET and Mono. What sets them ap
GDB, the GNU Project debugger, allows you to see what is going on `inside' another program while it executes -- or what another program was doing at the moment it crashed.
GNU DDD is a graphical front-end for command-line debuggers such as GDB, DBX, WDB, Ladebug, JDB, XDB, the Perl debugger, the bash debugger, or the Python debugger. Besides ``usual'' front-end features such as viewing source texts, DDD has become famous through its interactive graphical data display, where data structures are displayed as graphs.
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