That's all for this topic How to Compile Java Program at Runtime. Instance method of that class is called at runtime. Once the java file is compiled it is loaded using the class loader and an instance of that class is created. class files so that path is provided for the generated class. Here IĪlso in eclipse, by default, bin is the location for putting. Here it can be seen that n method is provided with the path of the class HelloWorld. HelloWorld instance = (HelloWorld)cls.newInstance() Giving the path of the class directory where class file is generated.įile classesDir = new File("C:\\workspace\\Test\\bin\\org\\test") ĬlassLoader = URLClassLoader.newInstance(new URL ) Ĭls = Class.forName("", true, classLoader) "C:\\workspace\\Test\\src\\org\\test\\HelloWorld.java")
In the next post I will give a brief introduction to HBase, how to install it, basic commands and how interface HBase with Hadoop.JavaCompiler compiler = ToolProvider.getSystemJavaCompiler() After running the jobs there should be a part-0000 file at /tmp/wordcount/out with the results.Īnd this is all for the moment. Places the files to count the words from at /tmp/wordcount/in and create an empty directory /tmp/wordcount/out to place the results.
Let’s add the following statement in the main method to check if Eclipse can resolve the import. Now we should get access to the Hadoop API. Right-click on Project, select Properties (Alt + Enter).Now compile the project: mvn clean installĬheck that the variable M2_REPO is added to the list of accessible libraries:
We will install the latest version of the 1.0 branch. The current 1.0 version is fork of 0.20.205. At the same same time the 0.20, 0.22 and 0.23 branches are also being developed. Currently, there are several branches going on. The development of Hadoop is very active. Now to run the project from command line: mvn exec:java -Dexec.mainClass = "" Add the following under : maven-compiler-plugin true 1.6 1.6 UTF-8 This way we can tell Maven which version of Java to use to compile our project. It is also a good idea to add a section specifying compiler configuration. Open it and add the following: exec-maven-plugin 1.2.1 java
This file contains all the descriptions need to manage a software project (configurations, plugins, dependencies, etc). All Maven projects have a pom.xml file in their root folder. To run the project from the command line, it is necessary first to add the Exec Maven Plugin. Or simply type ‘Shift + Alt + X’ and then ‘J’. Use -Dhbase.profile2.0 to build Hadoop with HBase 2.0.0-beta1. plan on running Timeline Service v2 with HBase 1.2.6. The official releases are ready to use if you. HBase 1.2.6 is used by default to build Hadoop.
If you don’t have it in your system, go to, download Eclipse classicand install it. Java version: 1.6.0_25, vendor: Sun Microsystems Inc.ĭefault locale: en_US, platform encoding: UTF-8 In case you already had Maven2 installed, installing Maven3 will make the mvn command to point to Maven3. It is possible to have both Maven3 and Maven2 in the same system. Maven is project management tool, similar to Ant or Make, that allow us to build a project, add dependencies and control many different aspects of the project. The project will be managed with Maven, and it will be able to execute Hadoop jobs from Eclipse. So in this post I will explain how to create a basic project with access to the Hadoop API.
How to install them, use them, create a basic Hadoop project, etc. Together with the presentation I promised the crowd there to post some introductory articles about Hadoop and HBase. The presentation is available here: “The Hadoop Stack: An overview of the Hadoop ecosystem”. It can be found in hadoop-common/lib, and. It does requires the snappy-java.jar is on the classpath. It contains the native libraries for many operating systems and instruction sets, falling back to a pure java implementation. Recently I gave a talk about the Hadoop ecosystem at Igalia’s Master Open Sessions. The Snapp圜odec uses the snappy-java compression library, rather than explicitly referencing native binaries.