Download CDC Build System Guide

4.4.4
Adding Classes to Preloaded Builds
Product-specific classes can be added to the list of preloaded classes. This feature can
be used for bundled applications and product-specific class libraries. Because the
preloaded classes are linked to the bin/cvm executable at build time, this process
cannot be undone at a later stage to regain space.
Here’s an example of how to add an application class file to the list of preloaded
classes:
1. Compile the Java application.
% javac HelloWorld.java
2. Edit build/linux-x86-suse/GNUmakefile and modify the definition of
CVM_JCC_INPUT to include the compile Java application:
CVM_JCC_INPUT += myclasses/HelloWorld.class
CVM_JCC_INPUT specifies the list of preloaded classes. The += syntax is necessary to
avoid overriding the values defined in share/jcc.mk.
3. Build the CDC Java runtime environment with preloading enabled.
% make
By itself, this technique will preload only those classes appended to
CVM_JCC_INPUT. To preload the full Java class library, use CVM_PRELOAD_SET=
libfull.
In this example, it is not necessary to define the class search path for HelloWorld
with the -cp command-line option at runtime because the class has been preloaded.
The difference in size between the cvm executable is not great because HelloWorld
is a small class. The benefits of faster launching and operation are more apparent
with larger applications.
4-10
CDC Build System Guide • December 2008