Java is a popular programming language used to write applications for computers, mobile phones, and embedded devices. It is an object-oriented language and its source code is compiled into bytecode, which can be executed on any Java Virtual Machine (JVM). There are many classes in Java that facilitate its use, and two of these are BufferedReader and Scanner. In this article, we’ll examine the differences between these two classes, when to use them, and their respective advantages and disadvantages.

What is the Difference Between a BufferedReader and Scanner?

The main difference between a BufferedReader and Scanner is that the former is used for reading data from an InputStream and the latter is used for reading data from files or strings. BufferedReader reads data line by line, whereas Scanner reads data token by token or word by word. The BufferedReader is also faster than the Scanner, as it reads from an InputStream directly.

In addition, BufferedReader is more suitable for reading large amounts of data, as it reads data in chunks, whereas Scanner is more suitable for reading small amounts of data. Furthermore, BufferedReader is more efficient in terms of memory usage, as it does not store the data it reads, whereas Scanner stores the data it reads in memory.

How to Use a BufferedReader

Using a BufferedReader is relatively straightforward. To use it, you’ll have to create a BufferedReader object and provide an input stream over which it will read data. This can either come from a file or somewhere else such as a server or a socket. After creating the object, you can call the readLine() method to read the data line by line.

Once you have read the data, you can use the close() method to close the BufferedReader and free up any resources it was using. It is important to remember to close the BufferedReader when you are done with it, as it can cause memory leaks if left open.

How to Use a Scanner

Using a Scanner is very similar to using a BufferedReader. You’ll need to create a Scanner object, and provide either a file, a string, or an input stream from which the data will be read. After the object is created, you can call the hasNext() method to check for available data. If there is data available, you can call the nextLine() or next() methods to read the data.

You can also use the Scanner class to parse primitive data types such as int, double, and boolean. To do this, you can use the nextInt(), nextDouble(), and nextBoolean() methods. Additionally, you can use the useDelimiter() method to specify a delimiter to use when parsing the data.

Advantages of Using a BufferedReader

The main advantage of using a BufferedReader is its speed. As it reads from an input stream directly, it can be much faster than a Scanner. Additionally, it provides more control over how data is read, as you can manipulate the buffered input with various classes such as byte arrays and some other useful classes.

Another advantage of using a BufferedReader is that it can read large amounts of data at once, which can be more efficient than reading small chunks of data at a time. Additionally, it can be used to read data from a variety of sources, such as files, network connections, and even strings. This makes it a versatile tool for reading data from different sources.

Advantages of Using a Scanner

A major advantage of using a Scanner is that it provides rich support for regular expressions. This makes it much easier to parse text and determine what type of data is being read. Additionally, you can specify different patterns for how data is read, making it easier to parse complex strings.

Another advantage of using a Scanner is that it can be used to read data from a variety of sources, including files, strings, and streams. This makes it a versatile tool for reading data from different sources. Additionally, it can be used to read data from multiple sources simultaneously, making it a great choice for applications that need to process data from multiple sources.

Disadvantages of Using a BufferedReader

The main disadvantage of using a BufferedReader is that you have to create your own parser for parsing the input and handling errors. Additionally, it can be difficult to use when you are dealing with large strings as reading from an input stream requires lots of system resources.

Another disadvantage of using a BufferedReader is that it can be slow when dealing with large amounts of data. This is because the BufferedReader reads data in chunks, which can take longer than reading the data in one go. Additionally, the BufferedReader can be difficult to debug, as it can be hard to track down the source of any errors.

Disadvantages of Using a Scanner

The main disadvantage of using a Scanner is that it can be slower than the BufferedReader as it parses the input data character by character whereas BufferedReader reads from the stream directly. Additionally, there may be some incompatibilities with some character encodings as the Scanner may not recognize all characters.

Another disadvantage of using a Scanner is that it can be difficult to debug. Since the Scanner is parsing the input data character by character, it can be difficult to identify where the issue is occurring. Additionally, the Scanner may not be able to handle large amounts of data efficiently, as it may take a long time to parse the data.

When to Choose a BufferedReader Over a Scanner

A BufferedReader should be used if you want the most efficient way to read data from an InputStream as it reads directly from the stream and does not require any parsing of the input. This can be especially useful when dealing with large datasets or files.

BufferedReader also allows you to read data line by line, which can be useful when dealing with text files. Additionally, BufferedReader can be used to read data from a file in a specific encoding, which can be useful when dealing with internationalization or localization.

When to Choose a Scanner Over a BufferedReader

If you are dealing with smaller datasets or files or if you need to parse complex strings, then it’s better to use a Scanner as this will give you better control over how the data is read and parsed. Additionally, its support for regular expressions makes it easier to parse more complex types of input.

Scanner also provides a wide range of methods for reading different types of data, such as reading a line of text, reading a single character, or reading a number. This makes it easier to read data from a variety of sources, such as files, strings, and streams. Furthermore, Scanner is also more efficient than BufferedReader, as it reads data in chunks, rather than reading the entire file at once.