NonStop Server for Java Programmer's Reference (NSJ 4.0+)

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Implementation Specifics
This section explains these subjects regarding HP implementations of NonStop Server for Java, based on
Java 2 Platform, Standard Edition, SDK 1.4.1, for NonStop systems:
Headless Support●
Additional Files●
Additional Environment Variable●
Java Native Interface (JNI)●
IEEE Floating-Point Implementation●
Linker and Compiler Options●
POSIX Threads●
Java Print Service (JPS)●
JavaBeans●
Debugging Java Programs●
Deviations in Java VM Specification Options●
Garbage Collection (GC)●
In addition, see Application Profiling.
Headless Support
Because the HP NonStop Kernel operating system does not provide support for windowing operations,
NonStop Server for Java 4 is a headless Java VM that conforms to the Sun Microsystems headless support
standard regarding Java Abstract Window Toolkit (AWT) classes and methods. For similar reasons, the
NonStop Server for Java 4 does not support the AppletViewer tool.
If your Java programs use classes and methods that require a display, keyboard, sound, or mouse operation,
the class or method will throw a HeadlessException if invoked when
GraphicsEnvironment.isHeadless returns true. This value is always true in NonStop Server for
Java 4.
Classes and methods that support printing, fonts, and imaging are fully supported in a headless Java VM.
While the Sun Microsystems documentation for the reference implementation states that you must set the
system property –Djava.awt.headless=true to run a headless Java VM, setting this system property
is unnecessary for NonStop Server for Java 4.