If you are using Eclipse:

• Run command: "mvn eclipse:eclipse" to generate Eclipse's project files
• Set your output path to "target/classes"

If you are using IntelliJ:

• Set your output path to "target/classes"
• Import the project's pom file
• Intellij will not auto-compile when you are running any example, so you have to choose either:
• Run the examples inside IntelliJ then you have to compile the class manually with (Alt+B E)
• Run the examples outside IntelliJ with the run_example*.bat

下文介绍比较详细 https://www.toptal.com/java/java-wizardry-101-a-guide-to-java-class-reloading