When I got something like this

ERROR/AndroidRuntime(18677): Caused by: java.lang.NullPointerException
ERROR/AndroidRuntime(18677):     at com.companyname.a.a.a(Unknown Source)

How can I know where the problem is and debug this issue? I only got the mapping output from ProGuard and don't know the line number. Thanks.

android debugging obfuscation proguard
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