General usage As explained by other answers, you can run with the following JVM options: -XX:+UnlockDiagnosticVMOptions -XX:+PrintAssembly Filter on a specific method You can also filter on a specific method with the following syntax: -XX:+UnlockDiagnosticVMOptions -XX:CompileCommand=print,*MyClass.myMethod Notes: you might need to put the second argument within quotes depending on OS etc. if the method gets … Read more
I want to understand purposes of this optimization. In what cases performance is increased, etc. Reference to some research of this problem will be great. The purpose is mainly to save memory, which also leads to faster code due to better cache efficiency. Basically, the Integer class keeps a cache of Integer instances in the … Read more
For certain versions of Java, you can check the bitness of the JVM from the command line with the flags -d32 and -d64. $ java -help … -d32 use a 32-bit data model if available -d64 use a 64-bit data model if available To check for a 64-bit JVM, run: $ java -d64 -version If … Read more
Had the same error encountered which was due to conflicting drawable resources. I did a clean project and the error was no longer encountered.
Run the JVM with -XX:MaxHeapSize=512m (or any big number as you need) (or -Xmx512m for short)
You can ask the Java Runtime: public class MaxMemory { public static void main(String[] args) { Runtime rt = Runtime.getRuntime(); long totalMem = rt.totalMemory(); long maxMem = rt.maxMemory(); long freeMem = rt.freeMemory(); double megs = 1048576.0; System.out.println (“Total Memory: ” + totalMem + ” (” + (totalMem/megs) + ” MiB)”); System.out.println (“Max Memory: ” + … Read more
From the Java documentation (not the javadoc API): http://download.oracle.com/javase/6/docs/technotes/guides/net/proxies.html Set the JVM flags http.proxyHost and http.proxyPort when starting your JVM on the command line. This is usually done in a shell script (in Unix) or bat file (in Windows). Here’s the example with the Unix shell script: JAVA_FLAGS=-Dhttp.proxyHost=10.0.0.100 -Dhttp.proxyPort=8800 java ${JAVA_FLAGS} … When using containers … Read more
This is really linked to HotSpot and the default option values (Java HotSpot VM Options) which differ between client and server configuration. From Chapter 2 of the whitepaper (The Java HotSpot Performance Engine Architecture): The JDK includes two flavors of the VM — a client-side offering, and a VM tuned for server applications. These two … Read more
To get an iterable set: Set<Thread> threadSet = Thread.getAllStackTraces().keySet(); Performance: 0 ms for 12 threads (Azul JVM 16.0.1, Windows 10, Ryzen 5600X).
Virtual memory used by a Java process extends far beyond just Java Heap. You know, JVM includes many subsytems: Garbage Collector, Class Loading, JIT compilers etc., and all these subsystems require certain amount of RAM to function. JVM is not the only consumer of RAM. Native libraries (including standard Java Class Library) may also allocate … Read more