APIs To Be Removed from Java 10

In the blog post "JDK 10 Release Candidate Phase", I looked at the twelve new features that are likely to be part of JDK 10. In this post, I look at some of the APIs that appear likely to be removed in JDK 10 and I look at some APIs proposed to be deprecated in JDK 10. The information in this post is based on the current version (2018/1/31 19:49 -0800 [a337d4f5aa79]) of "Java SE 10 (18.3) (JSR 383) Proposed Final Draft Specification - DRAFT" and, because this source document is a draft, this information is subject to change.

The JDK 9 enhanced deprecation feature (JEP 277) allowed several JDK APIs to be annotated with @Deprecated's new optional forRemoval() element to be set to true, which indicates that the annotated API "is earmarked for removal in a future release." The following APIs had this enhanced deprecation applied, were marked for "removal in a future release" in JDK 9, and now JDK 10 appears to be the version in which they'll be removed.

• "Remove terminally deprecated methods Runtime.getLocalized{Input,Output}Stream" (JDK-8193162)
  • java.lang.Runtime.getLocalizedInputStream(java.io.InputStream) (deprecated since JDK 1.1)
  • java.lang.Runtime.getLocalizedOutputStream(java.io.OutputStream) (deprecated since JDK 1.1)
• "Remove deprecated pre-1.2 SecurityManager methods and fields" (JDK-8189750)
  • java.lang.SecurityManager.classDepth(java.lang.String) (deprecated since JDK 1.2)
  • java.lang.SecurityManager.classLoaderDepth() (deprecated since JDK 1.2)
  • java.lang.SecurityManager.currentClassLoader() (deprecated since JDK 1.2)
  • java.lang.SecurityManager.currentLoadedClass() (deprecated since JDK 1.2)
  • java.lang.SecurityManager.getInCheck() (deprecated since JDK 1.2)
  • java.lang.SecurityManager.inClass(java.lang.String) (deprecated since JDK 1.2)
  • java.lang.SecurityManager.inClassLoader() (deprecated since JDK 1.2)

As currently proposed, JDK 10 will add the optional annotation element forRemoval=true to some previously deprecated [@Deprecated] API elements that did not formerly have forRemoval set. These include security-related interfaces, classes, and exceptions that have been replaced by other security-related constructs (many were replaced as far back as JDK 1.2). Several "finalize"-ending methods also have their @Deprecated annotation enhanced to indicate that as of JDK 10 they are "earmarked for removal in a future release." For example, FileInputStream.finalize() was deprecated in JDK 9, but will be marked with forRemoval=true as of JDK 10.

Most of the JDK API constructs to be removed in JDK 10 have been deprecated for a long time (since JDK 1.2 or earlier) and so there has been plenty of time to replace use of these. Most of the JDK API constructs newly denoted in JDK 10 to be removed in a future release have already been deprecated and this change is only to indicate that they now will likely be removed in a future release. The JDK 9-introduced enhanced deprecation mechanism allows the JDK API to have constructs more aggressively removed after having their likely removal advertised in advance via the forRemoval=true element of the @Deprecated annotation. JDK 9 removed several things and it appears likely that JDK 10 will continue the removal of certain previously deprecated API elements.