NetBeans configuration

Earlier in this chapter, we discussed the NetBeans user and cache directories and what information is stored within them. If you wish to change the user directory for a specific instance of NetBeans (for example, you may want to use a completely fresh user directory or a user directory from a previous installation of NetBeans), this can be achieved by specifying the netbeans_default_userdir parameter. Similarly, the cache directory can be changed by specifying the netbeans_default_cachedir parameter:

netbeans_default_userdir="${DEFAULT_USERDIR_ROOT}/8.0.2"
netbeans_default_cachedir="${DEFAULT_CACHEDIR_ROOT}/8.0.2"

The NetBeans default startup options are probably the most likely of the command-line arguments that you'll need to change for NetBeans. These options are specified by the netbeans_default_options parameter:

netbeans_default_options="-J-client -J-Xss2m -J-Xms32m -J-XX:PermSize=32m -J-Dapple.laf.useScreenMenuBar=true -J-Dapple.awt.graphics.UseQuartz=true -J-Dsun.java2d.noddraw=true -J-Dsun.java2d.dpiaware=true -J-Dsun.zip.disableMemoryMapping=true""true"

The preceding example options are from a Mac OS X installation of NetBeans 8.0.2.

The first option (-J-client) specifies that the JVM for NetBeans will run as a client VM instead of server VM. The client VM is essentially useful for applications requiring fast startup or small footprints. The server VM is typically used where performance is more important.

The second set of options (-J-Xss2m -J–Xms32m –J-XX:PermSize=32m) define the default memory allocation sizes used by the JVM running NetBeans (the thread stack size, initial memory allocation pool size, and size of the permanent generation, respectively). These options are specific for different version of the JDK, and all of them may not apply to the version of the JDK you are using.

The final parameters specified in the default options ensure that certain optimizations are performed on the JVM to make it more stable and perform better. Some of these parameters are operating system-specific and may not exist on configuration files for different operating system.

By default, NetBeans uses the system-defined JDK to run the IDE (you'll remember this can be overridden using the --javahome argument to the NetBeans installer, as discussed earlier in this chapter). This can be overridden in the netbeans.conf file by defining the netbeans_jdkhome property to specify the base directory of a different JDK installation:

netbeans_jdkhome="/path/to/jdk"

It's not usually necessary to change the JDK that NetBeans uses as this is set at the time of installation. However, if you wish to use a newer (or older) JDK than the one used when you installed NetBeans, it can be configured with this variable.

If you wish to run NetBeans as a one-off instance and do not wish to edit the netbeans.conf file, you can pass the --jdkhome <jdk_home> parameter on the command line instead when launching NetBeans.

A NetBeans cluster is a directory on disk that contains a set of modules such as the NetBeans Platform or the Java EE support within the NetBeans IDE. Additional clusters can be configured within NetBeans by adding the directory in which the cluster resides onto the netbeans_extraclusters parameter:

netbeans_extraclusters="/absolute/path/to/cluster1:/absolute/path/to/cluster2""cluster2"

It is most likely that you will not need to define the additional module clusters to be loaded at the startup unless you are developing NetBeans rich client platform (RCP) applications.

Several other NetBeans command-line arguments are available that provide more control over the NetBeans user experience.

To run NetBeans in a locale different from that of the operating system, the --locale option can be used. For example, --locale en:GB runs NetBeans with the en:GB locale.

If you wish to increase the base font size of NetBeans, the --fontsize option allows this to be achieved. For example, --fontsize 20 increases the base font size to 20px. This can be useful when demoing code or showing NetBeans to larger audiences.

The full list of different command-line options that are available within NetBeans is provided at http://wiki.netbeans.org/FaqStartupParameters.