$ javap -public java.lang.classfile.** on each JDK, then diff by class (24: OpenJDK Runtime Environment Temurin-24.0.2+12 (build 24.0.2+12), 26: OpenJDK Runtime Environment Temurin-26.0.2.1+1 (build 26.0.2.1+1)) === JDK 24 -> JDK 25 === + java.lang.classfile.ClassFile: public static final int JAVA_25_VERSION; ~ java.lang.classfile.attribute.UnknownAttribute was: public interface java.lang.classfile.attribute.UnknownAttribute extends java.lang.classfile.Attribute, java.lang.classfile.ClassElement, java.lang.classfile.MethodElement, java.lang.classfile.FieldElement { now: public interface java.lang.classfile.attribute.UnknownAttribute extends java.lang.classfile.Attribute, java.lang.classfile.ClassElement, java.lang.classfile.MethodElement, java.lang.classfile.FieldElement, java.lang.classfile.CodeElement { + java.lang.classfile.constantpool.ClassEntry: public abstract boolean matches(java.lang.constant.ClassDesc); + java.lang.classfile.constantpool.MethodTypeEntry: public abstract boolean matches(java.lang.constant.MethodTypeDesc); + java.lang.classfile.constantpool.ModuleEntry: public abstract boolean matches(java.lang.constant.ModuleDesc); + java.lang.classfile.constantpool.PackageEntry: public abstract boolean matches(java.lang.constant.PackageDesc); + java.lang.classfile.constantpool.StringEntry: public abstract boolean equalsString(java.lang.String); + java.lang.classfile.constantpool.Utf8Entry: public abstract boolean isFieldType(java.lang.constant.ClassDesc); + java.lang.classfile.constantpool.Utf8Entry: public abstract boolean isMethodType(java.lang.constant.MethodTypeDesc); 239 classes in old, 239 in new, 9 difference(s) === JDK 25 -> JDK 26 === + java.lang.classfile.ClassFile: public static final int JAVA_26_VERSION; 239 classes in old, 239 in new, 1 difference(s) === is it a preview API on JDK 24? === $ javap -v java.lang.classfile.ClassFile | grep -ci PreviewFeature 24.0.2+12: 0 25.0.5+8-LTS: 0 26.0.2.1+1: 0 === @since of ClassFile === jdk-24.0.2+12: * @since 24 jdk-25.0.5+8: * @since 24 jdk-26.0.2.1+1: * @since 24