Java.Streams.What is SequenceInputStream used for?

SequenceInputStream in Java is a class used to combine two or more input streams into one so they can be read sequentially, one after the other, as if they were a single continuous stream.

📦 Package

It is part of java.io package:

import java.io.SequenceInputStream;

🧠 Use Case

Imagine you have multiple files or streams, and you want to read them one after another in a single loop — SequenceInputStream helps with that.

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🔧 Constructors

1. Two streams:

SequenceInputStream(InputStream s1, InputStream s2)

Reads from s1 until it ends, then from s2.

2. Enumeration of streams:

SequenceInputStream(Enumeration<? extends InputStream> e)

Reads from a list of InputStreams provided as an Enumeration.

✅ Example

Combine two files into one stream:

FileInputStream file1 = new FileInputStream("file1.txt");
FileInputStream file2 = new FileInputStream("file2.txt");

SequenceInputStream sis = new SequenceInputStream(file1, file2);

int data;
while ((data = sis.read()) != -1) {
    System.out.print((char) data);
}

sis.close();
file1.close();
file2.close();

🧵 Summary

• Combines multiple input streams.
• Reads them in sequence.
• Useful for reading multiple files/streams as a single stream.