First of all you need to get the sources of all the open source used in the your project may be from internet or from author copyrighted.
manual approach :
- Where the license.txt file present-
- Get license name from License.txt file
- Note the licenses and related open source component in list-of-license.txt file
- where the license.txt file not-present-
- get the source code
- analysis and check in source code containing license.
e.g if apache-aop.jar does not have any license.txt file, get the source code from internet.
Note the licenses and related open source component in list-of-license.txt file
another approach with the help of open source scanning software tool:
You can use any other open source scanning tool which will list all the open source component and licenses possible matches used inside the project and you can make use of it.
open source tool list reference,
https://en.wikipedia.org/wiki/List_of_tools_for_static_code_analysis
Thanks,
Sandeep