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8 :     <title>Eclipse 3.3 Plug-in Migration FAQ</title>
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10 :    
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12 :    
13 :     <h1>Eclipse 3.3 Plug-in Migration FAQ</h1>
14 : johna 1.2 <ol>
15 :     <li><a href="#signing">Impact of JAR signing</a></li>
16 :     </ol>
17 :     <h2><a name="signing">Impact of JAR signing</a></h2>
18 :     <p>
19 :     In Eclipse 3.3, plug-ins in the Eclipse platform are signed with a cryptographic
20 :     signature supplied by the Eclipse Foundation. Signing of plug-ins can have an impact
21 : darin 1.3 in three areas:</p>
22 : johna 1.2 <ul>
23 :     <li>Code that uses non-Eclipse class loaders. Eclipse class loaders have a flag
24 :     that controls load-time verification of signature, and it is turned off by default. Loaders in
25 :     the JDK such as URLClassLoader do not have this option, and will always verify
26 :     any JAR file that contains signatures. If this performance impact is not acceptable,
27 :     the only solution is to avoid signing of JARs that are loaded by other class loaders.
28 :     A common example is JARs that are intended to be run with Ant. </li>
29 :     <li> Use of the constructor <tt>java.util.jar.JarFile(File)</tt> (i.e., without verify = false).
30 :     JarFile will perform verification of signatures unless explicitly told not to. This will
31 :     have a performance impact when the JAR is signed. If you don't need signature verification,
32 :     be sure to use the <tt>JarFile</tt> API that does not perform verification.</li>
33 :     <li>Use of <tt>java.util.jar.Manifest</tt>. Since the manifest file of a signed JAR can
34 :     be quite large, anyone reading and parsing entire manifest.mf files will see a
35 :     performance hit. The best solution in this case is to only read the manifest
36 :     main attribute rather than parsing the entire file.</li>
37 :     </ul>
38 : darin 1.3
39 : johna 1.2
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