This bug is extracted from the JDK-8251123. Instead of specifying this old/unused class, I suggest to delete it.

This is the comment added to this class in JDK 1.1.1:
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/*
 * In JDK 1.1.1, the pkg private class java.awt.PeerFixer was moved to
 * become an inner class of ScrollPane, which broke serialization
 * for ScrollPane objects using JDK 1.1.
 * Instead of moving it back out here, which would break all JDK 1.1.x
 * releases, we keep PeerFixer in both places. Because of the scoping rules,
 * the PeerFixer that is used in ScrollPane will be the one that is the
 * inner class. This pkg private PeerFixer class below will only be used
 * if the Java 2 platform is used to deserialize ScrollPane objects that were serialized
 * using JDK1.1
 */