Google Summer Of Code 2009 Projects Proposals

Subject ID

harmony-tools-1

Title

Implement a Java developer's command line tool

ASF Project

Apache Harmony

Keywords

Java, tools

Description

Harmony is missing several of the tools that ship with the JDK, including jar, jconsole and javaws. For this task you would implement one of these tools, either in Java or C/C++ if preferred.

Possible Mentors

Oliver Deakin (committer), Mark Hindess (committer)

Status

Unassigned

Subject ID

harmony-tools-2

Title

Implement the jdb command line debugger tool

ASF Project

Apache Harmony

Keywords

Java, tools, jdb

Description

jdb is the command line debugger tool provided as part of the basic JDK tools (

). For this task you would implement the jdb debugger, in C/C++ and/or Java

Possible Mentors

Oliver Deakin (committer), Mark Hindess (committer)

Status

Unassigned

Subject ID

harmony-tools-3

Title

Extend VMTT bytecode assembler

ASF Project

Apache Harmony

Keywords

Java, tools, vmtt

Description

VMTT is a bytecode assembler used to test the Apache Harmony VM and class library. For this task, you would extend it in several ways: adding real labels (so one could write jsr loop instead of jsr -5), adding flexibility to emit more bad classes (specifying padding and values explicitly for tableswitch/lookupswitch, allowing double/long constant pool entries without a subsequent constant pool entry), allowing for mixed asm and bin in methods, allowing for insertion of binary data in other places (such as the constant pool), warning users of possible errors (such as bad code_length for a given code array (configurable)), and fixing existing defects. If legal approval is available, you might extend VMTT to read the JASM format as well.

Possible Mentors

Andrew Cornwall

Status

Unassigned

Subject ID

harmony-i18n-tool

Title

Automatic localization tool for open source project

ASF Project

Apache Harmony

Keywords

open source project, localization,automatic translation

Description

The Harmony Project has no localized data for worldwide customers. This project plans to create an automatic tool that helps projects to translate the necessary messages. The tool will automatically extract the messages, conduct analysis if necessary to translate, translate and adjust, and at last inject into the source code with ResourceBundle or property loading mechanism and apply the localization. There are many open source projects in existence, most of which do not have localized messages for customer convenience, including the Harmony project, so the tool may also be helpful on a wider scale. (

)

Possible Mentors

Jing Lv (Jimmy) (committer)

Status

Unassigned

Subject ID

harmony-daemon

Title

Running multi-programs on one Harmony VM

ASF Project

Apache Harmony

Keywords

multi-programs on single VM

Description

In Java, we usually run one program on one VM. However there are many advantages to executing multiple programs on one jvm, e.g. memory usage, startup time, etc. However there are many potential conflicts that could be caused e.g. the vm will meet an exit() or fatal error in one program, which causes the other programs to fail together. This project is concerned with finding a clever solution for running multiple Java programs on a single VM.

Possible Mentors

Xu ruizhi(Regis), Jing Lv (Jimmy) (committer)

Status

Unassigned

Subject ID

harmony-classes-selector

Title

• Smallest classes set for customer application*

ASF Project

Apache Harmony

Keywords

smallest class set for application

Description

Many Java desktop applications offer a JRE in the installation package, which may be big. Customising the JRE to be the smallest size to run an application takes a lot of effort. We are looking for an automatic tool to find out all classes used by an application and build up a smallest JRE for the customer. (

)

Possible Mentors

Xu ruizhi(Regis), Jing Lv (Jimmy) (committer), Li JinQing(Charles)

Status

Unassigned

Subject ID

harmony-osgi

Title

• Enable OSGi features for Harmony JDK*

ASF Project

Apache Harmony

Keywords

OSGi, JDK

Description

OSGi is hot and Apache Harmony has already make it's modules into OSGi bundles. If the Harmony runtime itself can include an OSGi framework, it will help other projects executing on a Harmony JRE to be OSGi without implementing an OSGi framework themselves. If we can go a little further, it may make the Harmony Project the first OSGi-ed JDK on the world and could enable an update mechanism for Harmony easily. (

)

Possible Mentors

Zhou Kai(Kevin), Jing Lv (Jimmy) (committer)

Status

Unassigned

Subject ID

harmony-portlib

Title

Portability in Apache Harmony: portlib, the Apache Portable Runtime or a new alternative

ASF Project

Apache Harmony

Keywords

Harmony, APR

Description

To enable the Harmony class library to be easily ported to new platforms a portability library exists. By replacing components in the portability library a VM may integrate with the Harmony libraries. Alternatively a VM may use and build on the portability library with Harmony. No current VM builds on top of just the portability library. The IBM VMs use bespoke OS integration, DRLVM uses this and the Apache Portable Runtime (APR), Jikes RVM uses the Harmony portability library and limited bespoke OS integration. The Apache Portable Runtime differs from the Harmony portability library in that virtual memory functions are exposed via mmap/munmap/mprotect rather than reserve/free/commit/decommit. The Harmony portability library used to but no longer provides a portable signal handling mechanism. This project will create a portability strategy for VMs using the Harmony class library either by using the Harmony portability library, the Apache Portable Runtime or potentially with no wrapper layer. One option is to recode the Harmony portability library entirely using the APR, adding support for signal handling whilst also adding support to APR for a different means of managing virtual memory. Another option is to put the portability library functionality into APR. Alternatively no wrappers and adopting UNIX conventions may best suppport portability. Ideally multiple open source Harmony VMs can be tested with this portability layer such as DRLVM and Jikes RVM. This project will require consultation with Harmony developers to form agreement and consensus on a portability strategy. Documenting this strategy will also form part of the project.

Possible Mentors

Ian Rogers, Alexei Fedotov (committer)

Status

Unassigned

Subject ID

harmony-zlib

Title

• Improve Apache Harmony zlib/zip performance*

ASF Project

Apache Harmony

Keywords

Java, zlib, Zip

Description

There are a number of changes that should improve zlib performance for Harmony such as using the inflateBack api (compare gzip/gun in the zlib distribution), exploiting parallelism (compare gzip/pigz) and/or using mmap rather than file operations. The project would be to implement these techniques to see what works in practice.

Possible Mentors

Mark Hindess (committer)

Status

Unassigned

Subject ID

harmony-JIT-1

Title

• Modularize Harmony JIT by separating JET as a standalone JIT compiler*

ASF Project

Apache Harmony

Keywords

Harmony, JVM, JIT, modularity

Description

So far the JIT component (called Jitrino) of Harmony has virtually two JIT implementations: JET and OPT. Jitrino.JET is a fast but non-optimizing JIT, and Jitrino.OPT is an optimizing JIT. The code base of JET and OPT shares lots of code hence they are mixed in one module. This is undesirable for situations where people need only JET, for fast compilation, for small footprint. This project proposes to create a standalone JET-based JIT module for Harmony. It does not require to remove JET from Jitrino, but to create a new JIT module with JET. This project is also a very good exercise to examine the JIT modularity design, the interface between JIT and other components, the interaction between multiple co-existing JIT modules.

Possible Mentors

Xiao-Feng Li (committer)

Status

Unassigned

Subject ID

harmony-GC-1

Title

• Implement WeakReference support in Harmony concurrent GC*

ASF Project

Apache Harmony

Keywords

Harmony, concurrent GC, weak reference

Description

Harmony already has a concurrent GC (called Tick, with three concurrent GC algorithms). It runs well with standard benchmarks. The only remaining unfinished feature is WeakReference support . Weakly referenced object (i.e., referent) is accessed through get() interface. That means, get() operation can make a weakly reachable referent strongly reachable. During concurrent collection, the system must monitor the get() operation to catch this change of reachability, otherwise the referent could be reclaimed. This project also includes to integrate the WeakReference processing with Finalization process. Other optimizations in Tick are also desirable, such as to reduce the amount of floating garbage.

Possible Mentors

Xiao-Feng Li (committer)

Status

Unassigned