This package contains an example program that demonstrates importing a Java library distributed as a Jar file into Swift and using some APIs from that library. It demonstrates how to:

• Use the swift-java tool to discover the classes in a Jar file and make them available in Swift
• Layer Swift wrappers for Java classes as separate Swift modules
• Access static methods of Java classes from Swift

This example wraps an open-source Java library implementing the Sieve of Eratosthenes algorithm for finding prime numbers, among other algorithms. To get started, clone that repository and build a Jar file containing the library:

git clone https://github.com/gazman-sdk/quadratic-sieve-Java
cd quadratic-sieve-Java
sh ./gradlew jar
cd ..

Now we're ready to build and run the Swift program from Samples/JavaSieve:

swift run JavaSieve

The core of the example code is in Sources/JavaSieve/main.swift, using the static Java method SieveOfEratosthenes.findPrimes:

let sieveClass = try JavaClass<SieveOfEratosthenes>(environment: jvm.environment())
for prime in sieveClass.findPrimes(100)! {
  print("Found prime: \(prime.intValue())")
}