JChemPaint (or JCP for short here) is the editor and viewer included in CDK for 2D chemical structures. It is implemented in several forms: a Java application and two varieties of Java applet.

JChemPaint was started by Christoph Steinbeck in the late 1990's to be the complementary structure editor to Jmol. It was then co-developed by Egon Willighagen and others. Jmol again is a visualisation and analysis tool for 3D molecular structures, started by Dan Gezelter at Notre Dame University, initiator of the Open Science Project and, like JChemPaint, developed by an international team of opensource programmers.

In at least three aspects JChemPaint is different from other 2D editors:

• JChemPaint is open source and free software. We believe that scientific software, especially when its development was publicly funded, should be free. As the GNU people put it: «`Free software´ is a matter of liberty, not price. To understand the concept, you should think of `free speech´, not `free beer´». Everyone can participate in the development of the program. Everyone can download and change the source code, provided that they make the changes publicly available again, according to the GNU Lesser General Public License, LGPL. This ensures that the community can take advantage of any bugfix or enhancement made to the system. It also ensures that a scientist, who needs a standard piece of software like a structure editor as a helper application in his/her new program, does not have to reinvent the wheel over and over again because all the structure editors that have been written before are now proprietary software. If there is a free structure editor, he/she can focus on the real science.
• JChemPaint is in constant development and you can help (see below).
• Since JChemPaint is written in Java, it runs on any computing platform and operating system for which a Java Virtual Machine (of version >= 1.3 up to JCP 2.4 and version >= 1.5 for JCP > 2.4) has been implemented (like Linux, Windows, Solaris, AIX and others).
• JChemPaint is available free of charge.
• JChemPaint is translated into several languages: Dutch, French, German, Polish, Portuguese and Spanish.

集成EditorApplett到jsp頁面里:

<applet code="org.openscience.jchempaint.applet.JChemPaintEditorApplet"
archive="jchempaint-applet-core.jar" name="Editor"
width="550" height="400">
</applet>

集成ViewerApplet到jsp頁面里:
<applet code="org.openscience.jchempaint.applet.JChemPaintViewerApplet"
archive="jchempaint-applet-core.jar"
width="550" height="400">

Applet methods:

Reading from the applet

• getMolFile()
• getSmiles()
• getSmilesChiral()
• getParameter()
• getParameterInfo()
• getAppletInfo()
• getLocale()
• getImage()
• getTheJcpp()

Writing to the applet

• setMolFile()
• setMolFileWithReplace()
• addMolFileWithReplace()
• loadModelFromUrl()
• loadModelFromSmiles()
• clear()
• selectAtom()
• init()
• start()
• stop()
• initPanelAndModel()
• setTheJcpp()
• setTheModel()