29:00 set maximum heap size 29:35 argument to the JVM: 29:43 -Xmx (maximum heap size) 30:00 examplevalue: -Xmx10m 30:28 OutOfMemoryError in runtime 30:58 a tool that comes with JDK - J visual M 33:06 monitor tab
According to here the String Intern Pool now is part of the heap from java 7 but note that it this varies from one JVM implementation to another. There's no permgen in Java 8.www.oracle.com/technetwork/java/javase/jdk7-relnotes-418459.html#jdk7changes. According to the stackoverflow answer here (stackoverflow.com/questions/4918399/where-does-javas-string-constant-pool-live-the-heap-or-the-stack) : quoting "...All strings in the JVM string pool are eligible for garbage collection if there are no references to them from your program roots. It applies to all discussed versions of Java. It means that if your interned string went out of scope and there are no other references to it - it will be garbage collected from the JVM string pool. Being eligible for garbage collection and residing in the heap, a JVM string pool seems to be a right place for all your strings, isn’t it? In theory it is true - non-used strings will be garbage collected from the pool, used strings will allow you to save memory in case then you get an equal string from the input. Seems to be a perfect memory saving strategy? Nearly so. You must know how the string pool is implemented before making any decisions."
29:00 set maximum heap size
29:35 argument to the JVM: 29:43 -Xmx (maximum heap size)
30:00 examplevalue: -Xmx10m
30:28 OutOfMemoryError in runtime
30:58 a tool that comes with JDK - J visual M
33:06 monitor tab
Excellent explenation ! maan... you are a boss :)
great explenation ! :)
a very nice tutorial :)
Where do we find the example programs you are using in your video series. Please let us know.
For more information please look at our website www.virtualpairprogrammers.com/ Many thanks
Who and when the string pooling are cleaned? Works the same in both permgen and metaspace?
According to here the String Intern Pool now is part of the heap from java 7 but note that it this varies from one JVM implementation to another. There's no permgen in Java 8.www.oracle.com/technetwork/java/javase/jdk7-relnotes-418459.html#jdk7changes. According to the stackoverflow answer here (stackoverflow.com/questions/4918399/where-does-javas-string-constant-pool-live-the-heap-or-the-stack) :
quoting "...All strings in the JVM string pool are eligible for garbage collection if there are no references to them from your program roots. It applies to all discussed versions of Java. It means that if your interned string went out of scope and there are no other references to it - it will be garbage collected from the JVM string pool. Being eligible for garbage collection and residing in the heap, a JVM string pool seems to be a right place for all your strings, isn’t it? In theory it is true - non-used strings will be garbage collected from the pool, used strings will allow you to save memory in case then you get an equal string from the input. Seems to be a perfect memory saving strategy? Nearly so. You must know how the string pool is implemented before making any decisions."