Sdkmanager "Error: Could not find or load main class com.android.sdklib.tool.sdkmanager.SdkManagerCli" on Windows

Open the sdkmanager.bat in a text editor and add echo %CLASSPATH% just below the CLASSPATH=%APP_HOME%\...\sdkmanager-classpath.jar. Then run sdkmanager --help which will echo the CLASSPATH of the required file. And check whether is it the valid path.

In my case, it was the wrong path,

It said my sdkmanger-classpath.jar is in lib folder. But it was not! It was actually inside the lib/_ folder. So as the simple solution what I did was copy the content in side lib/_ folder to lib. Then it worked fine!

1. Download the SDK tools ZIP (Under Command Line Tools in https://developer.android.com/studio).
2. Unzip using 7zip. Avoid using the default windows extractor - that doesn't do the extraction correctly.
3. After unzipping using 7zip, place the contents into the sdk folder (C:\Users\<username>\AppData\Local\Android\Sdk\tools\bin and C:\Users\<username>\AppData\Local\Android\Sdk\lib) and run sdkmanager on command prompt.

As @Chrishan wrote Avoid using default windows extractor.

You can use the PowerShell:

Expand-Archive  commandlinetools....zip  C:\Android\Sdk