Day 18: 🧠 Transformers 101 — What They Are and Why They Matter

Learn what Transformers are in AI, how they power models like GPT and BERT, and why every Java developer working with LLMs should understand them.

📌 Part of the 30 Days of AI + Java Tips — simple, powerful AI concepts for developers building smarter systems.

🤖 What Is a Transformer in AI?

In simple terms:

A Transformer is a type of deep learning model architecture that uses attention to process and understand text, code, and other sequences — in parallel.

It’s the architecture behind:

• GPT (ChatGPT, GPT-4)
• BERT
• T5
• LLaMA
• Claude
  …and many more.

So, if you’re building anything using LLMs — you’re already using Transformers.

⚙️ Why Transformers Replaced RNNs & LSTMs

Before Transformers, models read one token at a time (like a human reading slowly).

Problems:

• Can’t handle long-range dependencies well
• Difficult to parallelize
• Slow training