JavassistProxyFactory fails if it cannot write to /tmp/com/zaxxer/.../*.class

[xkr47]

It seems JavassistProxyFactory dumps generated proxy classes to a directory structure directly below the operating system tmp directory. At least in Unix environments this directory is typically shared, so if another user tries to use HikariCP as well, he gets an exception when failing to overwrite the files dumped by the first user.

Perhaps the path where temporary files are written (by HikariCP) could be made user-specific e.g. adding System.getProperty("user.name") into the path, to allow multiple users to use HikariCP on the same machine?

Sample stacktrace snippet:

java.lang.ExceptionInInitializerError: null
        at com.zaxxer.hikari.HikariConfig.<clinit>(HikariConfig.java:86) ~[sb-consumer-SNAPSHOT.1.jar:na]
        ...
Caused by: java.lang.RuntimeException: java.lang.RuntimeException: java.lang.RuntimeException: java.io.FileNotFoundException: /tmp/com/zaxxer/hikari/proxy/ConnectionJavassistProxy.class (Permission denied)
        at com.zaxxer.hikari.proxy.JavassistProxyFactory.<clinit>(JavassistProxyFactory.java:60) ~[sb-consumer-SNAPSHOT.1.jar:na]
        ... 97 common frames omitted
Caused by: java.lang.RuntimeException: java.lang.RuntimeException: java.io.FileNotFoundException: /tmp/com/zaxxer/hikari/proxy/ConnectionJavassistProxy.class (Permission denied)
        at com.zaxxer.hikari.proxy.JavassistProxyFactory.<init>(JavassistProxyFactory.java:97) ~[sb-consumer-SNAPSHOT.1.jar:na]
        at com.zaxxer.hikari.proxy.JavassistProxyFactory.<clinit>(JavassistProxyFactory.java:55) ~[sb-consumer-SNAPSHOT.1.jar:na]
        ... 97 common frames omitted
Caused by: java.lang.RuntimeException: java.io.FileNotFoundException: /tmp/com/zaxxer/hikari/proxy/ConnectionJavassistProxy.class (Permission denied)
        at javassist.CtClass.debugWriteFile(CtClass.java:1478) ~[sb-consumer-SNAPSHOT.1.jar:na]
        at com.zaxxer.hikari.proxy.JavassistProxyFactory.generateProxyClass(JavassistProxyFactory.java:189) ~[sb-consumer-SNAPSHOT.1.jar:na]
        at com.zaxxer.hikari.proxy.JavassistProxyFactory.<init>(JavassistProxyFactory.java:85) ~[sb-consumer-SNAPSHOT.1.jar:na]
        ... 98 common frames omitted
Caused by: java.io.FileNotFoundException: /tmp/com/zaxxer/hikari/proxy/ConnectionJavassistProxy.class (Permission denied)
        at java.io.FileOutputStream.open(Native Method) ~[na:1.7.0_60]
        at java.io.FileOutputStream.<init>(FileOutputStream.java:221) ~[na:1.7.0_60]
        at java.io.FileOutputStream.<init>(FileOutputStream.java:110) ~[na:1.7.0_60]
        at javassist.CtClass$DelayedFileOutputStream.init(CtClass.java:1493) ~[sb-consumer-SNAPSHOT.1.jar:na]
        at javassist.CtClass$DelayedFileOutputStream.close(CtClass.java:1518) ~[sb-consumer-SNAPSHOT.1.jar:na]
        at java.io.FilterOutputStream.close(FilterOutputStream.java:160) ~[na:1.7.0_60]
        at java.io.FilterOutputStream.close(FilterOutputStream.java:160) ~[na:1.7.0_60]
        at javassist.CtClass.writeFile(CtClass.java:1431) ~[sb-consumer-SNAPSHOT.1.jar:na]
        at javassist.CtClass.debugWriteFile(CtClass.java:1473) ~[sb-consumer-SNAPSHOT.1.jar:na]
        ... 100 common frames omitted

[holgerstolzenberg]

I think that configuring the base path for writing the tmp files should be considered also.

[chrisvest]

I think these classes should be held entirely in memory, unless a flag for debugging proxy class generation says otherwise.

[holgerstolzenberg]

Also agree on that. Not sure though if in-memory persistence may yield other problems (heap consumption).

[brettwooldridge]

Classes are only dumped to the tmp dir when DEBUG level logging is set -- dumping the classes is not operational, but is in fact used for debugging. There are three options here:

• Turn off DEBUG level logging (typically not used in production)
• Turn off DEBUG level logging for the class JavassistProxyFactory
• Set the java.io.tmpdir directory (system property) to wherever you would like the temporary files to be written

[xkr47]

Ok, turning off DEBUG logging for JavassistProxyFactory sounds like the best option for us, thanks!

[xkr47]

Perhaps it would still be nice for those actually using the dumping feature that the files would be in a user-specific directory?

[brettwooldridge]

It's really just for internal use. We're going to change it over to an internally defined system property rather than triggering off of the debug mode of the logger.