how to validate testnet and mainnet bitcoin address via online api or offline for Android App? I would like to know web api provider to validate Mainnet &amp; Testet3 Bitcoin Address. 

How to validate a Bitcoin address is a real one?

Validate bitcoin address from android application

Gone through above references but Want a web service provider or local bitcoinJ type java library class.
Here are list of references to validate mainnet and testnet Bitcoin addresses:

Offline

IN JAVA

https://rosettacode.org/wiki/Bitcoin/address_validation#Java (mainnet + testnet)

https://github.com/timqi/btc_address_validator/blob/master/BTCAddrValidator.java (mainnet only)

IN GO

https://github.com/niksmac/btc-validate/blob/master/src/btc-validate.go

IN PHP

https://github.com/niksmac/btc-validate/blob/master/src/btc-validate.php

IN RUBY

https://github.com/niksmac/btc-validate/blob/master/src/btc-validate.rb

Online Api

https://blockexplorer.com/api/addr-validate/mjdkX5oxbc9ioTmbnRtc5g4Cojyr5esUuZ (mainnet + testnet)

Note: For around 30 languages we can take benefit of same by following reference:

https://rosettacode.org/wiki/Bitcoin/address_validation