Java : Serializable with Examples
December 14, 2022
Serializable (Java SE 19 & JDK 19) API Examples.
You will find code examples on most Serializable methods.
Summary
Serializability of a class is enabled by the class implementing the java.io.Serializable interface.
Please see also : Java Object Serialization Specification (Java SE 19)
public class Sample implements Serializable {
@Serial
private static final long serialVersionUID = -7890552026025073127L;
private final String text;
private final int num;
public Sample(String text, int num) {
this.text = text;
this.num = num;
}
@Override
public String toString() {
return "[text=%s, num=%d]".formatted(text, num);
}
}
final var file = Path.of("sample.data");
System.out.println(file); // sample.data
final var src = new Sample("abc", 123);
System.out.println(src); // [text=abc, num=123]
try (final var os = new ObjectOutputStream(Files.newOutputStream(file))) {
os.writeObject(src);
}
final var bytes = Files.readAllBytes(file);
// [-84, -19, 0, 5, 115, 114, 0, 6, 83, 97, 109, 112, 108, 101, -110, 127, 32,
// -68, -1, 9, 102, 25, 2, 0, 2, 73, 0, 3, 110, 117, 109, 76, 0, 4, 116, 101,
// 120, 116, 116, 0, 18, 76, 106, 97, 118, 97, 47, 108, 97, 110, 103, 47, 83,
// 116, 114, 105, 110, 103, 59, 120, 112, 0, 0, 0, 123, 116, 0, 3, 97, 98, 99]
System.out.println(Arrays.toString(bytes));
try (final var is = new ObjectInputStream(Files.newInputStream(file))) {
final var dst = is.readObject();
System.out.println(dst); // [text=abc, num=123]
System.out.println(dst.getClass().getSimpleName()); // Sample
}
Warning!
Deserialization of untrusted data is inherently dangerous. You should check the following official documentation.