jdk8

Think of studying Java, may learn openjdk is a better way, so go to find OPENJDK. The installation guide for the Debian based system is:sudo Install openjdk-8-jdkHowever, my Linux Mint 17 was unable to install. The following questions were found after the search:OpenJDK8 is included only in Ubuntu 14.10 and later versions of the sourceWhile Linux Mint 17 is based on Ubuntu 14.04LTS, the next version of Linux Mint 18 needs to be based on Ubuntu 16.04 LTS (officially announced only based on the LT

http://blog.csdn.net/qiyueqinglian/article/details/46605759The computer installed the Jdk8,java_home is also set 8.Do not delete 8 change back to 7.Changed the Java_home, and the C:\ProgramData\Oracle\Java\javapath in the path value was deleted.Run Java-version, errorError:registry key ' Software\javasoft\java Runtime environment ' \CurrentVersion 'Have value ' 1.8 ', but ' 1.7 ' is required.Error:could not find Java.dllError:could not find Java SE Ru

:/var/cache/oracle-jdk8-installer (JDK8)Below, and then install the installer once. Installer will use the TAR.GZ package you downloaded by default3. Set the system default JDKJDK8sudo update-java-alternatives-s java-8-oracleIf the JDK7 is installed and the JDK8 is installed, to switch between the two, you can:JDK8 Switch to Jdk7sudo update-java-alternatives-s ja

machine.Two time before the book, you have already talked about how to install and configure the free open source virtual machine software VirtualBox and how to install and configure CentOS7 in VirtualBox. In this article we will show you how to install JDK and Tomcat in CentOS7, for future needs, this article will describe how to install Oracle JDK8 and TOMCAT8.Software PreparationThis article uses tar.gz installation, of course, can also be install

the speed of the individual)If you cause installer to download slowly due to firewalls or other reasons, you can interrupt the operation. Then download the tar.gz package for the corresponding JDK, and put it in:/var/cache/oracle-jdk7-installer (JDK7)/var/cache/oracle-jdk8-installer (JDK8)Below, and then install the installer once. Installer will use the TAR.GZ package you downloaded by default3. Set the s

1. Background2. Why abandoned permanent generation (PermGen)3. In-depth understanding of meta-space (Metaspace)4. Summary======== Text Split Line =====First, the background 1.1 permanent generation (PermGen) where?According to this, the hotspot JVM structure is as follows (the virtual machine stack and the local method stack are up):Quoted from the network, but there is a problem: both the method area and the heap heap are thread-shared memory areas.About method areas and permanent generations:I

1.JDK installation PackageThe installation steps are slightly2.JDK and other configuration file modificationWhen installing JDK1.8 (this machine first installs the jdk1.7 again installs the jdk1.8), will Java.exe, Javaw.exe, javaws.exe three files copy to the C:\Windows\System32, This directory takes precedence over the environment variables set by Java_home in the WIN environment variable. So how we configure in Java_home will show java8 information.Solution:1. Delete the Java.exe in the C:\Win

The discovery is the JDK version of the problem, my system environment variable configuration is JDK7, but this war package needs to run in JDK8 environment. So I manually changed the JDK7 of the environment variable to JDK8, and the result found that the above problems still occur. So I opened cmd with java-version instructions to see, I am currently configured environment variables or JDK7, which I am puz

Install the JDK on your centos machine today and find that the previous tutorials are old and many things are out of date. Write the feeling of installation today.Determine if the installationFirst, we have to determine whether the machine is installed JDK, many people recommend the use of the Java-version command. Using the java-version command on my computer, the contents are as follows:Java Version "1.7.0_45"OpenJDK Runtime Environment (rhel-2.4.3.2.el6_4-i386 u45-b15)OpenJDK Server VM (build

) Designation of flags (flag)-embedded flag notation. 2, after obtaining the pattern instance, the method that can be used is: Split () Method: Cut the specified string by regular expressionMatcher () Method: Specify the string to compareFind () method: see if there is a next matching stringLookingat (): see if the beginning of the string matches the rule expressionGroup (): You can return a string that matches. 3, after obtaining the Matcher instance, the methods that can be

1. Background2. Why abandoned permanent generation (PermGen)3. In-depth understanding of meta-space (Metaspace)4. Summary======== Text Split Line =====First, the background 1.1 permanent generation (PermGen) where?According to this, the hotspot JVM structure is as follows (the virtual machine stack and the local method stack are up):Quoted from the network, but there is a problem: both the method area and the heap heap are thread-shared memory areas.About method areas and permanent generations:I

preservation.2. Problem Analysis:Based on the triggering conditions of the jdk8 Metaspace FULLGC, the initial metaspacesize is 38m means that the first GC (based on the features of JDK 8) when the first loaded class reaches 38m G1 and CMS will be well-collected in the Metaspace area (usually with full GC). ), and the JVM dynamically adjusts the size of the metaspacesize (after the GC is adjusted).Jdk8:meta

1. Check the installed JDKgrep JavaThe possible results are as follows:java-1.7.0-openjdk-1.7.0.99-2.6.5.0. El7_2.x86_64python-javapackages-3.4.1- One. El7.noarchjava-1.8.0-openjdk-headless-1.8.0.77-0. B03.el7_2.x86_64java-1.8.0-openjdk-1.8.0.77-0. B03.el7_2.x86_64tzdata-java-2016c-1. El7.noarchjavapackages-tools-3.4.1- One. El7.noarchjava-1.7.0-openjdk-headless-1.7.0.99-2.6.5.0. el7_2.x86_642. Removal of installed OPEN-JDK and dependent programsYum Remove tzdata-java-2016c-1. El7.noarchAll OPEN