machine learning tutorial java

To facilitate the understanding of the later learning, record!Run-time Data area1. Thread Sharing1.1 Method Area1.1.1 Running a constant-volume pool (runtime Constant)1.2 Heaps (heap)2. Thread-Private2.1 Virtual machine stack (VM stack)2.2 Local method Stack (Native)2.3 Procedure Counter (program Counter Register)3. Direct MemoryVirtual Machine Stack:Thread-priva

efficient. If the program allows, the unused reference object will be assigned null as soon as possible. This will speed up the GC's work.2. Use the Finalize function sparingly. The Finalize function is a chance that Java provides programmers with an opportunity to release objects or resources. However, it will increase the amount of GC work, and therefore minimize the use of a Finalize method to reclaim resources.3. If you need to use a frequently u

generations accounted for the memory size of-xmx corresponding to the value minus-xmn corresponding value. 5. Program counteris the smallest piece of memory area, its role is the current thread executes the byte code of the line number indicator, in the virtual machine model, the bytecode interpreter works by changing the value of this counter to select the next need to execute the byte code instruction, branch, loop, exception handlin

and two blocks of survivor space of the same size (usually called S0 and S1 or from and to), which can be specified by the-XMN parameter, or by-XX: Survivorration to adjust the size of Eden space and survivor space. old age: 5. Program Counter is the smallest piece of memory area, its role is the current thread executes the byte code of the line number indicato

, Dubbo distributed RESTful Service video tutorial First set:billions of traffic e-Commerce Details page System combat-cache Architecture + high-Availability service architecture + MicroServices Architecture (first edition)Second set:billions of traffic e-Commerce Details page System combat-cache Architecture + high-Availability service architecture + MicroServices Architecture (second edition) The third set:Elaticsearch Video Two sets-full version (c

heap, so different virtual machine implementations may have different access methods. There are two main ways of doing this: using handles and direct pointers.Handle Access : A chunk of memory is partitioned into the Java heap as a handle pool, where the handle address of the object is stored in the reference, and the handle contains the specific address information for the object instance data and the typ

succeeds, it returns a class reference to its service object-that is, the classloader that invokes it. Consider the security of the parent delegate loading mechanism.5/7It calls a lot of native methods, that is, using JNI to invoke the underlying C + + code.12. When a class is loaded, connected, initialized, its life cycle begins, when it represents the class objectThe life cycle of a class object ends when it is no longer referenced or is inaccessible. The data in the method area of the class

) at Com.xrq.test.ConstantPoolOverflowTest.main ( Constantpooloverflowtest.java:java.lang.OutOfMemoryError:PermGen space at Java.lang.ref.reference$referencehandler.run (Reference.java:123)Previously, for the hotspot, the method zone = Permanent generation, where the OutOfMemoryError area is "PermGen space", that is, the permanent generation, which is actually the method area overflow. Note that there is no such exception under the JDK1.7, while the loop will go on, because after JDK1.7 ov

that is automatically created by the virtual machine. " Execute " means that the virtual opportunity triggers this method, but does not promise to wait for it to end. Finalize () the more the object escapes the last chance of death, the GC will then make a second small-scale mark on the objects in the F-queue, and if the object is not escaped at this time, it can be recycled.Three, method recovery areamethod Area (HotSpot virtual

Last night written in-depth Java Virtual machine learning-the loading mechanism of the class to 1:30, because the next day to work, did not write the demo in the previous article, today take time to fill in the example of last night to explain.Here I first posted yesterday's two copies of the code, look again:classsingleton{Private StaticSingleton Singleton =NewS

each of the above three memory regions each time it performs GC, and most of the time it refers to the new generation. So the GC has two different types in the reclaimed area, one for the normal GC (minor GC) and one for the global GC (major GC or full GC), and they are for the following areas.Normal GC (minor GC): GC for Cenozoic regions only.Global GC (major GC or full GC): GC for all generational regions (Cenozoic, old generation, permanent generations).Because the GC effect is not good for

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the value is a non-leaf node (that is, an object reference), you can modify all the content underneath the node.Stacks and stacks are the most fundamental things that a program runs. A program can run without a heap, but not without a stack. The heap is a data storage service for the stack, and the heap is a shared memory. However, it is the idea of the separation of heaps and stacks that makes Java garbage collection possible.Java, the size of the s

1. Instantiation process: Cloning objects at the language level, creating objects, deserializing the generated objects by checking that the instantiated class is loaded (after the load, the class exists), whether it is parsed, initialized, and then allocates memory space (stored in the heap) for the new object, through the new keyword, the virtual opportunity, and the new directive. , sets the object header of the object instance, resets the object body to zero, and then executes the 2. Memory a