Why is stringbuffer thread safe?
How do you declare a string variable?
Can bool be null?
why not override thread to make a runnable? : Java thread
different between exception and error? explaim check and uncheck exception
What is the difference between length and length() method in java?
What is the final access modifier in java?
What is the argument in java?
What is percentage in java?
What is double in java?
what are upcasting and downcasting?
Difference between concurrent hashmap and hashtable and collections
What is java regex?