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$ java -agentlib:hprof[=options] appl_to_profile (JDK 1.5+)
$ java -Xrunhprof[:options] appl_to_profile (SDK 1.4.2.0+)
hprof supports a number of profiling options. Use java -Xrunhprof:help to display the
available options.
Following is an example hprof command to capture object data:
$ java -Xrunhprof:heap=dump Hello
Load the resulting text file into HPjmeter, jhat, hat, or any editor for analysis.
Following is an example using hprof to produce a text file with summarized statistical samples
taken every ten seconds during the execution of a Hello.java sample program:
$ java -Xrunhprof:cpu=samples Hello
For information about this tool on SDK 1.4 releases, refer to:
http://java.sun.com/j2se/1.4.2/docs/guide/jvmpi/jvmpi.html#hprof
For information about the updated version of this tool available on JDK 1.5+ releases refer to:
http://java.sun.com/developer/technicalArticles/Programming/HPROF.html
1.11 java.security.debug System Property
The java.security.debug system property controls whether the security checks in the JRE
(Java Runtime Environment) print trace messages during execution. This option can be useful
when trying to determine why a SecurityException is thrown by a security manager. This
system property can be set to one of the following values:
• access —print all checkPermission results
• jar —print jar verification information
• policy —print policy information
• scl —print permissions assigned by the SecureClassLoader
The access option has the following sub-options:
• stack —include stack trace
• domain —dump all domains in context
• failure —dump the stack and domain that did not have permission before throwing the
exception
For example, to print all checkPermission results and trace all domains in context, set
java.security.debug to access,stack. To trace access failures, set it to access,failure.
Following is an example showing the output of a checkPermission failure:
$ java -Djava.security.debug=”access,failure” Application
access denied (java.net.SocketPermission server.foobar.com resolve
)
java.lang.Exception: Stack trace
at java.lang.Thread.dumpStack(Thread.java:1158)
at java.security.AccessControlContext.checkPermission(AccessControlContext.java:253)
at java.security.AccessController.checkPermission(AccessController.java:427)
at java.lang.SecurityManager.checkPermission(SecurityManager.java:532)
at java.lang.SecurityManager.checkConnect(SecurityManager.java:1031)
at java.net.InetAddress.getAllByName0(InetAddress.java:1117)
at java.net.InetAddress.getAllByName0(InetAddress.java:1098)
at java.net.InetAddress.getAllByName(InetAddress.java:1061)
at java.net.InetAddress.getByName(InetAddress.java:958)
at java.net.InetSocketAddress.<init>(InetSocketAddress.java:124)
at java.net.Socket.<init>(Socket.java:178)
at Test.main(Test.java:7)
1.12 JAVA_TOOL_OPTIONS Environment Variable
The command line used to start an application is not always readily accessible in many
environments. This is especially true with applications that use embedded Java VMs or ones
where the startup is deeply nested in scripts. In these environments, the JAVA_TOOL_OPTIONS
1.11 java.security.debug System Property 37