Java Questions

A is wrong because a class can extend nly one class .B is wrong because a class can implement any number of interfaces.C is wronb because both can can be done simulteneously.So, D is correct

The finalize method is called by the garbage collector, just before releasing the object’s memory. It is normally advised to release resources held by the object inside the finalize method.

The Big-O notation simply describes how well an algorithm scales or performs in the worst case scenario as the number of elements in a data structure increases. The Big-O notation can also be used to describe other behavior such as memory consumption. Since the collection classes are actually data structures, we usually use the Big-O notation to chose the best implementation to use, based on time, memory and performance. Big-O notation can give a good indication about performance for large amounts of data.

A static method cannot access non static variables or methods because static methods doesnt need the object to be accessed. So if a static method has non static variables or non static methods which has instantiated variables they will no be intialized since the object is not created and this could result in an error.

Platform independence means that we can write and compile the java code in one platform (Eg Windows) and can execute the class in any other supported platform (Eg Linux,Solaris,etc).

There will always be a default constructor in every class 

PATH and CLASSPATH are operating system level environment variables. PATH is used to define where the system can find the executables (.exe) files whereas CLASSPATH is used to specify the location of .class files.