Its probably because you have introduced C++ native libraries in your App, to only debug java, click Run > Edit Configurations and then in the debugger tab, change Debug Type to Java
According to docs:
Because different debugger tools are required to debug Java/Kotlin
code and C/C++ code, the Android Studio debugger allows you to select
which debugger type to use. By default, Android Studio decides which
debugger to use based on which languages it detects in your project
(with the Auto debugger type)
The debug types available include the following:
Auto
automatically choose the best option for the code you are debugging.
For example, if you have any C or C++ code in your project, Android
Studio automatically uses the Dual debug type. Otherwise, Android
Studio uses the Java debug type.
Java
Select this debug type if you
want to debug only code written in Java or Kotlin—the Java debugger
ignores any breakpoints or watches you set in your native code.
Native (available only with C/C++ code)
Select this debug type if you want to
use only LLDB to debug your code. When using this debug type, the Java
debugger session view is not available. By default, LLDB inspects only
your native code and ignores breakpoints in your Java code. If you
want to also debug your Java code, you should switch to either the
Auto or Dual debug type.Select this debug type if you want Android Studio to