On devices running Android 5.0 to 5.1.1, the password lock screen (not the PIN or pattern locks) can be bypassed by crashing the screen UI. This can be accomplished by performing the following steps, as explained at https://android.gadgethacks.com/:

1. Click on the Emergency Call option on the lock screen and then enter any random input (for example, 10 asterisks) on the dialer screen.
2. Double-tap the field to highlight the entered text, as shown in the following screenshot, and select Copy. Now, paste it into the same field:

3. Repeat this process to add more characters. Do this until the field no longer highlights the characters on double-tapping.
4. Go back to the lock screen and open the camera shortcut. Now, pull down the notifications screen and tap the Settings icon. You will then be prompted to enter a password.

5. Press and hold the input field and select Paste, repeat this process multiple times. Once enough characters are pasted into the field, the lock screen will crash, allowing you to access the device.

Now, let's look at some more techniques.