The build error NoSuchFieldError: Class com.sun.tools.javac.tree.JCTree$JCImport does not have member field ‘qualid’ means an old Lombok (1.18.28 or older) is compiling on JDK 21 or newer. Upgrade Lombok to 1.18.48 in Maven, Gradle or the IDE and rebuild.
Use Java unnamed variables and patterns with _ in catch blocks, lambdas, loops and record patterns, and see where the underscore is a compile error.
Java scoped values are final in Java 25. Learn ScopedValue.where().run(), call(), rebinding, child threads and how scoped values compare with ThreadLocal.
Java record patterns with examples for instanceof, nested patterns, var, generics, sealed switch without default, null handling and MatchException.
Learn compact source files and instance main methods in Java 25 (JEP 512), formerly unnamed classes, with the IO class, implicit imports and rules.
Learn Java sequenced collections with examples of getFirst(), getLast(), reversed(), putFirst() and the exceptions and upgrade pitfalls to watch for.
Java 21 features with runnable examples for virtual threads, sequenced collections, record patterns and switch, plus each preview’s status in Java 25.
Java string templates were withdrawn in JDK 23 and do not exist in Java 25. See the old syntax, why it was dropped and the replacements that work today.
Java structured concurrency with the Java 25 preview API. Learn StructuredTaskScope.open(), fork, join, Joiners, timeouts, custom joiners and the flags.
Java virtual threads explained for Java 25 with examples, carrier threads, the Java 24 pinning fix, when not to use them, pooling and ThreadLocal pitfalls.
HowToDoInJava provides tutorials and how-to guides on Java and related technologies.
It also shares the best practices, algorithms & solutions and frequently asked interview questions.
