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  Find files by size in Linux

In Linux systems, you may encounter a situation where there is no enough space on the system while you are trying to install some new packages or writing some data. In this case, you may want to clear some unneeded files. A frequent need will be find the largest files in the system so that they can be deleted first and disk space can be released quickly. In this post, we will show a simple command to find files by size so that we know what files are taking the specified space on the system, This...

   LINUX,FILESIZE,FIND     2020-04-25 08:02:45

  ByteBuffer in Java

ByteBuffer is introduced in java.nio since Java 1.4. It provides a way of representing raw structured data such as from a file or from network. It enables fast access of underlying data compared to traditional ways like byte[] Prior to Java 1.4, if you want to represent a structured raw data, you need to create a byte[] and then having a set of checks to delimit the byte array to get the expected tokens. There are three ways to create a ByteBuffer: Wrapping an exiting array by calling ByteBuffe...

   JAVA,BYTEBUFFER,ALLOCATION     2015-07-08 03:17:44

  Why to opt for Hadoop?

Hadoop is a open source that stores and processes big data. The framework is written in Java for distributed processing and distributed storage of very large data. Hadoop is Scalable. It is a scalable platform because it stores and distributed large amount of data sets to hundreds and thousands of servers that operate in parallel. Traditional database systems cannot process large amount of data. But, hadoop enable business to run applications involving thousands of Terabyte data. Hadoop is ...

       2015-09-22 10:17:43

  Set file permission in Java

Prior to Java 6,  there is no good solution at the Java level to provide file permission management. You need to implement your own native methods or call the Runtime.exec() to invoke the system routine such as chmod in LInux. Since Java 6, Java introduces a set of methods which can be used to set the file permission at Java level. These methods include: File.setReadable(boolean); File.setWritable(boolean); FIle.setExecutable(boolean); File.setReadable(boolean, boolean); File.setWritable(bo...

   JAVA, FILE PERMISSION, POSIX,learnjava     2015-08-29 03:37:37

  Microsoft to lay off Zune

Recently we can see many news about Microsoft's Windows 8, Microsoft puts much effort to promote Windows 8.  A few days ago, Microsoft announced the death of Windows Live brand, instead they will integrate it into the Windows system. Also, Microsoft now plans to lay off its Zune and focus on XBox, let XBox be the main entertainment service of Microsoft. XBox can provide  music and videos, it can also let users play video games.Here is a part of Microsoft's announcement:This year, Xbox ...

   Windows 8,Zune,XBox,Microsoft,Layoff     2012-05-30 08:14:58

  JavaScript Is Not A Language

Recently people presented arguments for and against using CoffeeScript. I felt the argument against was pointless and obviously wrong, but I couldn't figure out why, and I thought the counterargument for was kind of toothless and irrelevant. I've figured out the real issue.The real argument for CoffeeScript is that JavaScript is not really a language.Years ago I read something which explained, in my opinion, why Lisp has never achieved the mainstream adoption its passionate advocates belie...

   JavaScript,Not a language,CoffeeScript,Model     2011-12-29 08:46:15

  Recursive class initialization in Java

When a Java class is referenced and initialized, it has to go through the loading and linking first. Once the loading and linking complete successfully. The class will be initialized. The static variables and constant variables will be initialized during this process. Once the class is initialized, it is ready for use. If when class A is initialized and it is referencing a class B, the class B will also get initialized. But what will happen if class B is referencing class A as well? This is call...

   Java,JVM,class initialization,static final     2015-04-15 21:04:29

  What kind of automated testing does Facebook do?

We do several kinds of testing. Some specifics:For our PHP code, we have a suite of a few thousand test classes using the PHPUnit framework. They range in complexity from simple true unit tests to large-scale integration tests that hit our production backend services. The PHPUnit tests are run both by developers as part of their workflow and continuously by an automated test runner on dedicated hardware. Our developer tools automatically use code coverage data to run tests that cover the ...

   Facebook,Testing,PHP,Automated testing     2012-02-28 08:10:10

  Oracle released an urgent Java patch

On March 23, Oracle just released an urgent Java patch which is out of its normal update schedule. The security vulnerability is related to the Java SE running in web browsers on desktops. The CVE ID for this issue is CVE-2016-0636. With the unpatched Java, attackers can remotely exploit the target system without username and credentials. Successful exploits can impact the availability, integrity, and confidentiality of the user's system. When the user access pages containing malicious code...

   JAVA,SECURITY,ORACLE,NEWS     2016-03-25 08:39:59

  Hexadecimal and long in Java

Today I encountered a hexadecimal operation problem when I was implementing a bit reverse function for integer type. Basically in the implementation, there is an operation which is to do the bit operation & between one long integer and a hexadecimal number 0x00000000FFFFFFFFF. I was expecting that the high 32 bits of the long integer will be zeroed. But unfortunately I didn't get the expected result. The basic implementation is: long num=0x00F0_0000; num = (num>>16) | (num<<16); ...

   Hexadecimal,long,Java,bitwise operation     2014-06-18 23:44:32

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