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Hi Babneet, sorry for a late reply, created <a href="https://bugs.openjdk.org/browse/JDK-8354563">
https://bugs.openjdk.org/browse/JDK-8354563</a> to track this. Unfortunately JDK developers are busy with other areas and work may be slow, so feel free to contribute a patch if you want to.</div>
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Also javap problems usually go to the compiler-dev list instead of the jdk-dev list, which is usually more about changes with all-jdk impact, such as governance. Thank you for asking the appropriate list.</div>
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Regards, Chen Liang</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> jdk-dev <jdk-dev-retn@openjdk.org> on behalf of Babneet Singh <sbabneet@ca.ibm.com><br>
<b>Sent:</b> Monday, February 24, 2025 12:08 PM<br>
<b>To:</b> jdk-dev@openjdk.org <jdk-dev@openjdk.org><br>
<b>Subject:</b> Clarification on javap's -bootclasspath Behavior in JDK 24</font>
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<div dir="ltr">One or more of the following files ( object_i.txt ) violates IBM policy and all attachment(s) have been removed from the message.<br>
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Hi,</div>
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I would like to inquire about changes to javap's -bootclasspath option in JDK 24. In previous versions, -bootclasspath allowed overriding classes in the java.base module. However, I have observed different behavior in JDK 24 when using javap -bootclasspath.</div>
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I have attached object_i.jar (as object_i.txt; it should be renamed before use), which contains a modified version of the java.lang.Object class with an injected field: private int i. In JDK 23, using -bootclasspath successfully overrides the default java.lang.Object
class with this modified version. However, in JDK 24, the override does not occur. The observed behaviour across JDK23 and JDK24 is shown below.</div>
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Is this new behavior intentional (part of a new feature), or is it a bug? I couldn't find a mailing list specifically for javap. If this is not the appropriate mailing list for this inquiry, I would appreciate guidance on where to direct my question.<br>
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Regards,</div>
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Babneet</div>
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<b>Observed Behavior:</b></div>
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<b>==== JDK 23 and Prior Versions ====</b></div>
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<b># jdk23/Contents/Home/bin/javap -p -bootclasspath object_i.jar java/lang/Object</b></div>
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Compiled from "Object.java"</div>
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public class java.lang.Object { <b>// Injected field shows up</b></div>
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private int i;</div>
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public java.lang.Object();</div>
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protected java.lang.Object clone() throws java.lang.CloneNotSupportedException;</div>
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public boolean equals(java.lang.Object);</div>
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protected void finalize() throws java.lang.Throwable;</div>
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public final native java.lang.Class<? extends java.lang.Object> getClass();</div>
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public int hashCode();</div>
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public final native void notify();</div>
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public final native void notifyAll();</div>
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public java.lang.String toString();</div>
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public final void wait() throws java.lang.InterruptedException;</div>
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public final void wait(long) throws java.lang.InterruptedException;</div>
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public final void wait(long, int) throws java.lang.InterruptedException;</div>
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private final native void waitImpl(long, int) throws java.lang.InterruptedException;</div>
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private java.lang.Object newInstancePrototype(java.lang.Class);</div>
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}</div>
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<b>==== JDK 24 ====</b></div>
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<b># jdk24/Contents/Home/bin/javap -p -bootclasspath object_i.jar java/lang/Object</b></div>
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Compiled from "Object.java"</div>
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public class java.lang.Object { <b>// Injected field doesn't show up</b></div>
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public java.lang.Object();</div>
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public final native java.lang.Class<?> getClass();</div>
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public native int hashCode();</div>
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public boolean equals(java.lang.Object);</div>
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protected native java.lang.Object clone() throws java.lang.CloneNotSupportedException;</div>
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public java.lang.String toString();</div>
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public final native void notify();</div>
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public final native void notifyAll();</div>
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public final void wait() throws java.lang.InterruptedException;</div>
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public final void wait(long) throws java.lang.InterruptedException;</div>
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private final native void wait0(long) throws java.lang.InterruptedException;</div>
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public final void wait(long, int) throws java.lang.InterruptedException;</div>
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protected void finalize() throws java.lang.Throwable;</div>
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}</div>
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