Hi Ravi,
Tried running the script multiple times but no success. Even checked the keyboard settings but not found "Appium Android Input Manager" in the keyboard list.
After trying mentioned ways on web. I just thought to try other way, even though it is not correct but I had spent more time with this issue I tried following shortcut method:
After getting soft keyboard I just refreshed the page.
webdriver.navigate().refresh();
Please let me know if you have any suggestion.
Thanks Ravi.