I was using guava 14 to do String hashing like so: Hashing.sha256().newHasher().putString("String").hash().toString(); => 4d1ca6dce72e20ce214b706168340683bb6b571a7c977c1a9fe029a1cc1c4d06 just upgraded to guava16, calling this... Read More | Share it now!
Tag Archives: java
HashMap遍历的两种方式
第一种: Map map = new HashMap(); Iterator iter = map.entrySet().iterator(); while (iter.hasNext()) { Map.Entry entry = (Map.Entry) iter.next(); Object key = entry.getKey(); Object val = entry.getValue(); }... Read More | Share it now!
java.lang.IllegalAccessError: tried to access method com.google.common.base.Stopwatch.()V
java.lang.IllegalAccessError: tried to access method com.google.common.base.Stopwatch.()V from class org.apache.hadoop.mapred.FileInputFormat at org.apache.hadoop.mapred.FileInputFormat.getSplits(FileInputFormat.java:312) at... Read More | Share it now!
Linux:CentOS install gradle
Ensure that this packages are installed: yum install bzip2 yum install unzip yum install wget Use this shell to install gradle. Copy this content in a file /tmp/gradle.sh cat > /tmp/gradle.sh #!/bin/bash # installs to /opt/gradle #... Read More | Share it now!
Fatal error compiling: invalid target release: 1.7
Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.2:compile (default-compile) on project api: Fatal error compiling: invalid target release: 1.7 -> 根据错误提示invalid target release:... Read More | Share it now!
Downloading Apache Maven 3.3.9
https://maven.apache.org/download.cgi wget http://mirror.cogentco.com/pub/apache/maven/maven-3/3.3.9/binaries/apache-maven-3.3.9-bin.tar.gz tar xzvf apache-maven-3.3.9-bin.tar.gz mvn clean install // Skip all unittests -DskipTests ... Read More | Share it now!
JVM调优总结 -Xms -Xmx -Xmn -Xss
堆大小设置 JVM... Read More | Share it now!
JAR 打包命令详解
转自：Matrix-与Java共舞... Read More | Share it now!
怎样用java生成GUID与UUID
GUID是一个128位长的数字，一般用16进制表示。算法的核心思想是结合机器的网卡、当地时间、一个随机数来生成GUID。从理论上讲，如果一台机器每秒产生10000000个GUID，则可以保证（概率意义上）3240年不重复。 UUID是1.5中新增的一个类，在java.util下，用它可以产生一个号称全球唯一的ID import... Read More | Share it now!
Class Not Found Exception in Mapreduce wordcount job
2016-07-18 11:51:36,921 WARN org.apache.hadoop.mapred.YarnChild: Exception running child : java.lang.RuntimeException: java.lang.ClassNotFoundException: Class MyNLineInputFormat$MyNLineInputFormatMapper not found at... Read More | Share it now!