Synchronized methods in Java are used primarily to prevent multiple threads from accessing and modifying shared resources simultaneously, ensuring thread safety. This is crucial in multithreading scenarios where multiple threads may otherwise interfere with each other when accessing shared data.

To establish a connection to a specified URL in Java, you use the openConnection() method provided by the URL class. This method returns a URLConnection object, which can be used to interact with the resource located at the URL.

The worst-case time complexity of the Quick Sort algorithm is O(n^2). However, on average, it has a time complexity of O(n log n), making it a very efficient sorting algorithm for large datasets. The worst-case scenario occurs when the pivot chosen is always the smallest or largest element, resulting in unbalanced partitions.

The concat() method in Java combines two strings, and in this case, it appends "Programming" to "Java," resulting in "JavaProgramming." Therefore, the correct output is "JavaProgramming."

In JDBC, the ResultSet interface provides methods like first(), last(), next(), and previous() to navigate through the result set obtained from a database query. The other options are not related to ResultSet navigation in JDBC.

To create a pause in your animation without using a separate thread, you can use the PauseTransition class in JavaFX. It allows you to add a pause between animations or transitions. The other options are not intended for creating animation pauses without separate threads.

In Java, the keyword new is used to instantiate an object inside its own class definition. When you use new, you create a new instance of the class and allocate memory for it. The other options are not used for this purpose.

Starting from Java 8, interfaces in Java can have both abstract and static methods. This enhancement allows interfaces to have default method implementations using the 'default' keyword and static utility methods. However, they still cannot have instance variables.

Method overloading in Java occurs when there are multiple methods in a class with the same name but different parameters. This is a form of polymorphism and allows you to use the same method name for operations that are logically related but take different inputs.

"Hello" will not be printed at all because the condition in the while loop is false from the start. In a while loop, the code block inside the loop will only execute if the condition is true. Since the condition is false, the code block is never executed.