Not able to run TestNG test

Question

I am getting the below error on running TestNG test. Kindly suggest what could be wrong.

Note: I have installed TestNG v 708 from Eclipse IDE. My project is not a Maven Project so I have not added any dependency, it's a normal Java project.

[RemoteTestNG] detected TestNG version 7.8.0
Exception in thread "main" java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory
    at org.testng.log4testng.Logger.lambda$getLogger$0(Logger.java:30)
    at java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1708)
    at org.testng.log4testng.Logger.getLogger(Logger.java:30)
    at org.testng.TestNG.<clinit>(TestNG.java:113)
    at org.testng.remote.support.RemoteTestNGFactory7_8.createRemoteTestNG(RemoteTestNGFactory7_8.java:16)
    at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:67)
Caused by: java.lang.ClassNotFoundException: org.slf4j.LoggerFactory
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
    ... 6 more

How can I resolve it?