Problem Statement
What is incremental compilation and how does it improve build performance?
Explanation
Incremental compilation compiles only modified source files and their dependencies instead of recompiling entire codebase. Build tools track file changes using timestamps or content hashes, identifying which files need recompilation. This dramatically reduces build time for large projects where typically only small percentage of code changes between builds.
Gradle incremental compilation tracks input/output files:
```groovy
tasks.withType(JavaCompile) {
options.incremental = true
}
```
Maven uses incremental flag:
```bash
mvn compile -Dmaven.compiler.incremental=true
```
TypeScript/JavaScript bundlers (webpack, esbuild) use incremental builds by default, caching compiled modules. Factors affecting incremental builds: file dependency graphs (changing core files triggers more recompilation), cache management, build tool configuration. Combined with dependency caching and parallel execution, incremental compilation achieves fastest possible builds. Understanding incremental compilation is crucial for optimizing large project build times in CI/CD.
