Promil Promil is a part of IDR solutions team. She excels in AI, Data Science, Generative AI,Digital Marketing, Content Writing, and Graphic Designing .

Are you a Java Developer working with Image files?

Read and write images in Java with JDeli

What is LZW compression?

2 min read

lzw compression

What is LZW compression?

LZW is a lossless data compression. LZW algorithm, developed by Abraham Lempel, Jacob Ziv and Terry Welch, uses a dynamically created dictionary to convert data strings into codes. LWZ is commonly used in GIF image formats, certain TIFF image variants and PDF files.

How does LZW compression work?

LZW compression is a “greedy algorithm” that works by building shorter dictionary code of recurring data strings sequences and compressing the data efficiently.

What is the code table in LZW compression?

The code table stores character sequences from the input data. The code table starts with 256 standard characters and adds up to 4,096 entries from repeating data patterns. It allows the algorithm to recognize and compress repetitive patterns efficiently. During decompression, the table is rebuilt, translating codes back into their original sequences.

Does LZW compression affect quality?

Usually no, LZW compression is a lossless compression method. This means that when data is compressed using LZW and then decompressed, it will be restored to its original form without any loss of quality. Always ensure both the compressor and decompressor are compatible and are following the same standards.

What are the limitations of LZW Compression?

LZW compressions limitations include being less effective on non-repetitive data and historical patent issues. It also demands significant memory, can be slower for large files, and has potential security vulnerabilities.

How does LZW handle new or unseen data during compression?

If LZW encounters a string not in its dictionary, it adds the string and outputs the code for its known prefix. The dictionary dynamically grows as new sequences are found.

Can we compress encrypted data by LZW Compression?

Yes, LZW compression can be used to compress encrypted data. However, it is important to note that it does not provide any additional security for your data. You can read about JDeli if you have security concerns.

How can I handle the performance issues with LZW compression?

You should consider using optimized libraries, employing parallel processing, and caching frequently accessed decompressed data. JDeli stands out in this realm, with users noting up to a “55% reduction of read times for files” when leveraging its optimized framework with other standard solutions.

How to handle memory issues while using large dictionaries in LZW compression?

You can consider using adaptive techniques that reset or shrink the dictionary when it reaches a certain size. Alternatively, you can explore variations of LZW or other compression algorithms that are designed to handle larger data sets more efficiently.

How can I ensure data integrity when working with LZW compression?

You can use libraries that run entirely on local servers, avoiding any external calls or cloud-based operations. JDeli offers a robust solution by operating securely on your servers. It doesn’t make any callbacks or accesses to external clouds.

How can we efficiently manage LZW-compressed image formats?

The ideal tool should seamlessly handle formats like GIF and TIFF, which commonly utilize LZW compression, ensuring versatility and ease for developers. JDeli is a one stop solution for providing comprehensive support for these formats.

How can I choose the right compression algorithm?

Choose a compression algorithm based on your data type and requirements: DEFLATE for varied data, BZIP2 or LZMA for optimal text compression.

How can I integrate JDeli  into existing applications?

JDeli’s ImageIO plugin ensures that integration is seamless. Developers can replace standard and ImageIO.write commands with and JDeli.write, or they can utilize the ImageIO plugin with existing code.

If you have further questions related  to LWZ compression, please email us.

Find out how to read and write images files in Java with JDeli:

Read: BufferedImage image =;

Write: JDeli.write(myBufferedImage, OutputFormat.HEIC, outputStreamOrFile)

Learn more >>

Promil Promil is a part of IDR solutions team. She excels in AI, Data Science, Generative AI,Digital Marketing, Content Writing, and Graphic Designing .