Using ant or mvn to build a Java project
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I: ant
1. read the webpage http://ant.apache.org/manual/index.html about how to install ant

2. try to find build.xml in your project, if there are multiple build.xml files, use the one that is at a higher level of the directory tree

3. run "ant" in the folder enclosing "build.xml"
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II: maven
1. for windows, read the webpage http://maven.apache.org/guides/getting-started/windows-prerequisites.html, for linux, simply run "sudo apt install mvn"

2. try to find pom.xml in your project, if there are multiple pom.xml files, use the one that is at a higher level of the directory tree

3. run "mvn compile" in the folder enclosing "pom.xml"