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environment: class loaders


Resin organizes resources and classloaders into nested environments. Each environment context merges its own configuration with configuration inherited from the parent environment. Each environment context: server, host, web-app, etc. may be configured with any of the environment configuration tags.

Classloaders

class-loader

Adds dynamic classloaders to the current environment.

Each environment (<server>, <host>, <web-app>) etc, can add dynamic classloaders. The environment will inherit the parent classloaders. Each <class-loader> is comprised of several implementing loader items: library-loader for WEB-INF/lib, compiling-loader for WEB-INF/classes, even make-loader for more complex auto-compilation.

<class-loader> in resin-web.xml
<web-app xmlns="http://caucho.com/ns/resin">
  <prologue>
    <class-loader>
      <compiling-loader path="WEB-INF/classes"/>

      <library-loader path="WEB-INF/lib"/>
    </class-loader>
  </prologue>
</web-app>

compiling-loader

Configures an auto-compiling WEB-INF/classes-style class loader.

The compiling-loader will automatically compile Java code into .class files loading them.

compiling-loader Attributes
ATTRIBUTEDESCRIPTIONDEFAULT
argsAdditional arguments to be passed to the Java compilernone
batchIf true, multiple changed *.java files will be compiled in a single batchtrue
encodingI18N encoding for the Java compilernone
pathFilesystem path for the class loaderrequired
sourceJava source directoryvalue of path
require-sourceIf true, .class files without matching .java files will be deletedfalse

library-loader

Configures a jar library, WEB-INF/lib-style class loader.

The library-loader will add jar files in its path to the current classpath. Jar files are recognized when they have a filename extension of .jar or .zip.

library-loader Attributes
ATTRIBUTEDESCRIPTIONDEFAULT
pathFilesystem path for the class loaderrequired

See com.caucho.loader.DirectoryLoader.

tree-loader

Configures a jar library, WEB-INF/lib-style class loader similar to <library-loader>, but will also find .jar and .zip files in subdirectories.

tree-loader Attributes
ATTRIBUTEDESCRIPTIONDEFAULT
pathFilesystem path for the class loaderrequired

See com.caucho.loader.TreeLoader.

make-loader

Configures a custom make-style loader.

servlet-hack

Use of servlet-hack is discouraged. Using servlet-hack violates the JDK's classloader delegation model and can produce surprising ClassCastExceptions.

servlet-hack reverses the normal class loader order. Instead of parent classloaders having priority, child classloaders have priority.

simple-loader

Configures a simple classes-style class loader.

.class files in the specified directory will be loaded without any special compilation steps (in contrast with compiling-loader.)

simple-loader Attributes
ATTRIBUTEDESCRIPTIONDEFAULT
pathFilesystem path for the class loaderrequired
prefixClass package prefix to only load to a subset of classesnone

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