Page History

...

Code Block

bgColor	#FFcccc

public class SensitiveClass extends Exception {
  public static final SensitiveClass INSTANCE = new SensitiveClass();
  private SensitiveClass() {
    // Perform security checks and parameter validation
  }

  protected int printBalance() {
    int balance = 1000;
    return balance;
  }
}

class Malicious {
  public static void main(String[] args) {
    SensitiveClass sc = (SensitiveClass) deepCopy(SensitiveClass.INSTANCE);
    System.out.println(sc == SensitiveClass.INSTANCE);  // Prints false; indicates new instance
    System.out.println("Balance = " + sc.printBalance());
  }

  // This method should not be used in production quality code
  static public Object deepCopy(Object obj) {
    try {
      ByteArrayOutputStream bos = new ByteArrayOutputStream();
      new ObjectOutputStream(bos).writeObject(obj);
      ByteArrayInputStream bin = new ByteArrayInputStream(bos.toByteArray());
      return new ObjectInputStream(bin).readObject();
    } catch (Exception e) { 
      throw new IllegalArgumentException(e);
    }
  }
}

See rule MSC11 MSC07-J. Prevent multiple instantiations of singleton objects for more information on singletons.

...

<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="9f2ba3b6b0bcb200-49f90533-421946fd-ab18bf3f-02efed37375202232da188ad"><ac:plain-text-body><![CDATA[	[[Bloch 2005	AA. Bibliography#Bloch 05]]	Puzzle 83: Dyslexic Monotheism	]]></ac:plain-text-body></ac:structured-macro>
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="54c751689c11922f-8d886be8-4a8540d1-ba50bba6-421c518fe913f96ff7b6e843"><ac:plain-text-body><![CDATA[	[[Bloch 2001	AA. Bibliography#Bloch 01]]	Item 1: Enforce the singleton property with a private constructor	]]></ac:plain-text-body></ac:structured-macro>
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="0f391739414db0ce-e2c8edcd-49cd40ac-997f8d18-d1e807d870aa42c9732ff5f5"><ac:plain-text-body><![CDATA[	[[Greanier 2000	AA. Bibliography#Greanier 00]]	[Discover the secrets of the Java Serialization API	http://java.sun.com/developer/technicalArticles/Programming/serialization/]	]]></ac:plain-text-body></ac:structured-macro>
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="0a674cca0db543ed-e5838df4-4a27406b-9aaf9c20-c264095ca383725cd8baf4a8"><ac:plain-text-body><![CDATA[	[[Harold 1999	AA. Bibliography#Harold 99]]		]]></ac:plain-text-body></ac:structured-macro>
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="2974f8f5c945a571-fde0aaef-4e404e80-a76fa1ae-846d678d9c2a9a843772b079"><ac:plain-text-body><![CDATA[	[[JLS 2005	AA. Bibliography#JLS 05]]	[Transient modifier	http://java.sun.com/docs/books/jls/third_edition/html/classes.html#37020]	]]></ac:plain-text-body></ac:structured-macro>
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="924ae2a2c02c8e90-1ce7bc4a-499d4005-8290b057-ab6f600f7863fa966e505b24"><ac:plain-text-body><![CDATA[	[[Long 2005	AA. Bibliography#Long 05]]	Section 2.4, Serialization	]]></ac:plain-text-body></ac:structured-macro>
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="9c32250b9673ceda-a557775d-4afc4716-a79692a9-b14ab94c3dc2ff6b60e3af02"><ac:plain-text-body><![CDATA[	[[Sun 2006	AA. Bibliography#Sun 06]]	"Serialization specification: A.4 Preventing Serialization of Sensitive Data"	]]></ac:plain-text-body></ac:structured-macro>

...

Space shortcuts

Page tree

Versions Compared

Old Version 93

New Version 94

Key