Why are signals RED in color for stop?

1. Tell about the project 2. Question on equals and ==. 3. Swap two numbers without using third variable 4. WAP to list first 10 prime numbers. 5. Write a SQL for second max salary on employee table 6. Explain hashmap and weakhashmap. 7. Internal working of hashmap 7. Why are wait, notify and notifyall in object class 8. Analytical question: A man has 4 tablets - 2 red and 2 blue. The light goes on and he needs to take 1 red and 1 blue tablet.