How-to articles, tricks, and solutions about JVM

How can I tell if I'm running in 64-bit JVM or 32-bit JVM (from within a program)?

To determine whether you are running in a 64-bit JVM or a 32-bit JVM from within a Java program, you can use the sun.arch.data.model system property.

java jvm java-native-interface 64-bit 32-bit

How do I find out what keystore my JVM is using?

To find out which keystore the Java Virtual Machine (JVM) is using, you can use the javax.net.ssl.KeyManagerFactory class and the getDefaultAlgorithm method.

java jvm keytool

How do I set the proxy to be used by the JVM

To set the proxy to be used by the Java Virtual Machine (JVM), you can use the -Dhttp.proxyHost, -Dhttp.proxyPort, and -Dhttp.nonProxyHosts options when starting the JVM.

java jvm proxy

How to deal with "java.lang.OutOfMemoryError: Java heap space" error?

"java.lang.OutOfMemoryError: Java heap space" means that the application has exhausted the maximum heap space. To fix this error, you can try the following:

java jvm out-of-memory heap-memory

How to fix java.lang.UnsupportedClassVersionError: Unsupported major.minor version

The java.lang.UnsupportedClassVersionError error is usually caused by trying to run a Java class that was compiled with a newer version of the Java compiler than the version of the JRE (Java Runtime Environment) that you are using.

java jvm incompatibility unsupported-class-version

How to get a thread and heap dump of a Java process on Windows that's not running in a console

To get a thread and heap dump of a Java process on Windows that is not running in a console, you can use the jstack and jmap tools that are included with the Java Development Kit (JDK).

java jvm heap-dump thread-dump

What are the -Xms and -Xmx parameters when starting JVM?

The -Xms and -Xmx options are used to set the initial and maximum heap sizes, respectively, for the Java Virtual Machine (JVM).

java memory-management parameters jvm