jvm

问题 I am bit confused with the terms of cross platform and cross compiler. Let me be first clear about the cross platform. When people talk about cross platform it means the architecture of the CPU, i.e, X86 and X64 ? or the OS i.e windows 32 bit or Windows 64 (server or desktop)? UNIX doesn't have different flavours like 64 bit or 32 bit. Why so? .NET and java is cross compiler language, what it means? When the program is compiled in .NET, we have to choose the option like X86, X64 or Any CPU.

问题 I am bit confused with the terms of cross platform and cross compiler. Let me be first clear about the cross platform. When people talk about cross platform it means the architecture of the CPU, i.e, X86 and X64 ? or the OS i.e windows 32 bit or Windows 64 (server or desktop)? UNIX doesn't have different flavours like 64 bit or 32 bit. Why so? .NET and java is cross compiler language, what it means? When the program is compiled in .NET, we have to choose the option like X86, X64 or Any CPU.

问题 I am bit confused with the terms of cross platform and cross compiler. Let me be first clear about the cross platform. When people talk about cross platform it means the architecture of the CPU, i.e, X86 and X64 ? or the OS i.e windows 32 bit or Windows 64 (server or desktop)? UNIX doesn't have different flavours like 64 bit or 32 bit. Why so? .NET and java is cross compiler language, what it means? When the program is compiled in .NET, we have to choose the option like X86, X64 or Any CPU.

问题 I was playing around with jmap and found that simple "Hello World" Java program creates thousands of objects. Here is truncated list of objects Oracle JVM update 131 creates on startup: num #instances #bytes class name ---------------------------------------------- 1: 402 4903520 [I 2: 1621 158344 [C 3: 455 52056 java.lang.Class 4: 194 49728 [B 5: 1263 30312 java.lang.String 6: 515 26088 [Ljava.lang.Object; 7: 115 8280 java.lang.reflect.Field 8: 258 4128 java.lang.Integer 9: 94 3760 java.lang

问题 I was playing around with jmap and found that simple "Hello World" Java program creates thousands of objects. Here is truncated list of objects Oracle JVM update 131 creates on startup: num #instances #bytes class name ---------------------------------------------- 1: 402 4903520 [I 2: 1621 158344 [C 3: 455 52056 java.lang.Class 4: 194 49728 [B 5: 1263 30312 java.lang.String 6: 515 26088 [Ljava.lang.Object; 7: 115 8280 java.lang.reflect.Field 8: 258 4128 java.lang.Integer 9: 94 3760 java.lang

问题 I was playing around with jmap and found that simple "Hello World" Java program creates thousands of objects. Here is truncated list of objects Oracle JVM update 131 creates on startup: num #instances #bytes class name ---------------------------------------------- 1: 402 4903520 [I 2: 1621 158344 [C 3: 455 52056 java.lang.Class 4: 194 49728 [B 5: 1263 30312 java.lang.String 6: 515 26088 [Ljava.lang.Object; 7: 115 8280 java.lang.reflect.Field 8: 258 4128 java.lang.Integer 9: 94 3760 java.lang

问题 While using async-profiler I run the profiles for cpu and alloc separately but was hoping it would be possible to use them as part of the same duration? Given the output format types supported, this only seems to make sense if JFR is used. 回答1: Yes, this feature is implemented in v2.0 branch of async-profiler. The branch is currently under development, use with care. Planned for the next major release. To specify multiple events in the command line, use profiler.sh -e cpu,alloc -f out.jfr ...

问题 I am trying to use Notepad++ as my all-in-one tool edit, run, compile, etc. I have JRE installed, and I have setup my path variable to the .../bin directory. When I run my "Hello world" in Notepad++, I get this message: java.lang.UnsupportedClassVersionError: test_hello_world : Unsupported major.minor version 51.0 at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClassCond(Unknown Source) ......................................... I think the problem here is

问题 I am trying to use Notepad++ as my all-in-one tool edit, run, compile, etc. I have JRE installed, and I have setup my path variable to the .../bin directory. When I run my "Hello world" in Notepad++, I get this message: java.lang.UnsupportedClassVersionError: test_hello_world : Unsupported major.minor version 51.0 at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClassCond(Unknown Source) ......................................... I think the problem here is

问题 The question is can we cache jclass and jmethodID across different JNI methods invocation? I faced some strange behavior when trying to create an object of some specific class with cached jclass and jmethodID from another JNI method invocation. Here is a simple example: public class Main { static { System.loadLibrary("test-crash"); } public static void main(String args[]) throws InterruptedException { Thread.sleep(20000); doAnotherAction(doSomeAction()); } private static native long