Tracing tools

Tracing is a technique that presents details of the execution of your program. If you are able to follow the path of execution, you will gain a better insight into how your program runs and interacts with its environment.

Also, you will be able to pinpoint locations where your program starts to deviate from its expected behavior.

The tracing tools on Linux® are strace and ltrace. The command man strace displays a full set of available options.

strace

The strace tool traces system calls. You can either use it on a process that is already available, or start it with a new process. strace records the system calls made by a program and the signals received by a process. For each system call, the name, arguments, and return value are used. strace allows you to trace a program without requiring the source (no recompilation is required). If you use strace with the -f option, it will trace child processes that have been created as a result of a forked system call. You can use strace to investigate plug-in problems or to try to understand why programs do not start properly.

To use strace with a Java™ application, type strace java <class-name>.

You can direct the trace output from the strace tool to a file by using the -o option.

ltrace

The ltrace tool is distribution-dependent. It is very similar to strace. This tool intercepts and records the dynamic library calls as called by the executing process. strace does the same for the signals received by the executing process.

To use ltrace with a Java application, type ltrace java <class-name>