Question

Research predefined java packages. Select 2 packages and describe what they provide. Explain briefly what type of functionalities they provide. Give at least 2 example classes defined in each package you selected.

Answer 1

Package 1:

java.lang:

lang package provides classes which are fundamental for any Java program. Even if this package is not imported JVM automatically imports it. This packages consists of the following packages.

1. System,

2. String,

3. Object,

4. Thread,

5. Math,

6. Exception, etc.,

Package 2:

Java.io

io package provides the system input and output from files through serialization files/ data streams and file systems. The classes provided by this packages are used in all I/O operations including keyboard input. Classes are

1. FileInputStream,

2. FileOutputStream,

3. FileReader,

4. FileWriter,

5. RandomAccessFile,

6. BufferedReader,

7. BufferedWriter etc.