jvm如何用系统内存管理堆内存？
how does jvm manages heap memory with system memory?
1.HowJVM是用系统内存来管理堆内存吗？
2.What是我们在java编程中要注意的要点，以防止堆space问题？
java中的堆内存是什么？
When a Java program started Java Virtual Machine gets some memory from
Operating System. Java Virtual Machine or JVM uses this memory for all
its need and part of this memory is call java heap memory. Heap in
Java generally located at bottom of address space and move upwards.
whenever we create object using new operator or by any another means
object is allocated memory from Heap and When object dies or garbage
collected ,memory goes back to Heap space in Java
Jvm 堆管理？
As we know objects are created inside heap memory and Garbage
collection is a process which removes dead objects from Java Heap
space and returns memory back to Heap in Java. For the sake of Garbage
collection Heap is divided into three main regions named as New
Generation, Old or Tenured Generation and Perm space. New Generation
of Java Heap is part of Java Heap memory where newly created object
are stored, During the course of application many objects created and
died but those remain live they got moved to Old or Tenured Generation
by Java Garbage collector thread on Major or full garbage collection.
Perm space of Java Heap is where JVM stores Meta data about classes
and methods, String pool and Class level details. You can see How
Garbage collection works in Java for more information on Heap in Java
and Garbage collection.
java 编程要注意防止堆 space 问题？
When JVM starts JVM heap space is equal to the initial size of Heap
specified by -Xms parameter, as application progress more objects get
created and heap space is expanded to accommodate new objects. JVM
also run garbage collector periodically to reclaim memory back from
dead objects. JVM expands Heap in Java some where near to Maximum Heap
Size specified by -Xmx and if there is no more memory left for
creating new object in java heap , JVM throws
java.lang.OutOfMemoryError and your application dies. Before throwing
OutOfMemoryError No Space in Java Heap, JVM tries to run garbage
collector to free any available space but even after that not much
space available on Heap in Java it results into OutOfMemoryError. To
resolve this error you need to understand your application object
profile i.e. what kind of object you are creating, which objects are
taking how much memory etc. you can use profiler or heap analyzer to
troubleshoot OutOfMemoryError in Java. "java.lang.OutOfMemoryError:
Java heap space" error messages denotes that Java heap does not have
sufficient space and cannot be expanded further while
"java.lang.OutOfMemoryError: PermGen space" error message comes when
the permanent generation of Java Heap is full, the application will
fail to load a class or to allocate an interned string.
Try to use static variable and methods because they share commom memory.
1.HowJVM是用系统内存来管理堆内存吗？
2.What是我们在java编程中要注意的要点，以防止堆space问题？
java中的堆内存是什么？
When a Java program started Java Virtual Machine gets some memory from Operating System. Java Virtual Machine or JVM uses this memory for all its need and part of this memory is call java heap memory. Heap in Java generally located at bottom of address space and move upwards. whenever we create object using new operator or by any another means object is allocated memory from Heap and When object dies or garbage collected ,memory goes back to Heap space in Java
Jvm 堆管理？
As we know objects are created inside heap memory and Garbage collection is a process which removes dead objects from Java Heap space and returns memory back to Heap in Java. For the sake of Garbage collection Heap is divided into three main regions named as New Generation, Old or Tenured Generation and Perm space. New Generation of Java Heap is part of Java Heap memory where newly created object are stored, During the course of application many objects created and died but those remain live they got moved to Old or Tenured Generation by Java Garbage collector thread on Major or full garbage collection. Perm space of Java Heap is where JVM stores Meta data about classes and methods, String pool and Class level details. You can see How Garbage collection works in Java for more information on Heap in Java and Garbage collection.
java 编程要注意防止堆 space 问题？
When JVM starts JVM heap space is equal to the initial size of Heap specified by -Xms parameter, as application progress more objects get created and heap space is expanded to accommodate new objects. JVM also run garbage collector periodically to reclaim memory back from dead objects. JVM expands Heap in Java some where near to Maximum Heap Size specified by -Xmx and if there is no more memory left for creating new object in java heap , JVM throws java.lang.OutOfMemoryError and your application dies. Before throwing OutOfMemoryError No Space in Java Heap, JVM tries to run garbage collector to free any available space but even after that not much space available on Heap in Java it results into OutOfMemoryError. To resolve this error you need to understand your application object profile i.e. what kind of object you are creating, which objects are taking how much memory etc. you can use profiler or heap analyzer to troubleshoot OutOfMemoryError in Java. "java.lang.OutOfMemoryError: Java heap space" error messages denotes that Java heap does not have sufficient space and cannot be expanded further while "java.lang.OutOfMemoryError: PermGen space" error message comes when the permanent generation of Java Heap is full, the application will fail to load a class or to allocate an interned string.
Try to use static variable and methods because they share commom memory.