Steps for converting existing java project to maven project:
Install m2eclipse for maven plugin in eclipse. Please follow this link for installing m2eclipse plugin in eclipse.
Right click on project -> configure -> convert to maven project.
Provide group id and artifact id , I have kept them default.
Let me tell you more about group id and artifact id.
Group id : It uniquely identifies your project among all. So it may be something like com.companyname
Artifact id : It is name of jar or war without version. it may be something like project, so here we have put artifact id as ReadPropertiesFileJavaExample.
Click on finish button.
Just remember to put all dependencies in pom.xml
Bingo!! You have converted existing java project to maven project