notes on core java in java

A private variable may only be accessed within the class in which it is declared. In Java, if a variable is declared as private, it can only be accessed within the same class. Private access modifier restricts access to the members (variables or methods) to the class in which they are declared. This means that … Read more

String objects are constants. StringBuffer objects are not constants. In Core Java, the main difference between the String and StringBuffer classes lies in their mutability. Immutability (String): Strings in Java are immutable, meaning their values cannot be changed once they are assigned. Any operation that appears to modify a String actually creates a new String object. Example: java … Read more

A non-static inner class may have object instances that are associated with instances of the class’s outer class. A static inner class does not have any object instances. In Java, inner classes are classes that are defined within another class. There are two main types of inner classes: static inner classes and non-static (also known … Read more

No. An object cannot be cast to a primitive value. In Java, you cannot directly cast a Byte object to a double value. The reason is that they are not compatible types for a direct cast. If you have a Byte object and you want to convert it to a double, you can first convert … Read more

The read() method returns -1 when it has reached the end of a file. In Core Java, the read() method of the InputStream class returns an integer value. When it reaches the end of a file, it typically returns -1 to indicate the end of the stream. Here’s a simple example: java import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; public … Read more