Find Usages in Project Dependencies and JDK is a highly requested feature, especially from users working with J2EE projects or using maven. Issue 55291

The user expectation is that you will find all usages - there is no indication that non-project classes will be excluded, and it is quite a surprise when you are unable to use this basic feature to understand the way the JDK and libraries work. (At least the Go to Class dialog offers you the choice - F.U. does not.) There has been repeated feedback from users on this point.


Java's Find Usages support will be enhanced with searching in a project's dependencies. When the user invokes Find Usages on an element and selects a newly added scope in the dialog:

Current Project & Dependencies
Open Projects & Dependencies

the index will be queried for all resources that reference the element. Usages from these resources, binary or source, will be shown in the results window. In this window the user can filter the results with the already available filters and the newly added filters binary, dependency and platform.


In NetBeans 8.1 this enhancement will be enabled by default.

Command line option

Can be disabled by setting the cmdline option "".

Open Problems

Missing type references in the byte code

  • Missing Annotations with RetentionPolicy.SOURCE
  • Missing unused imports
  • Missing field access on constants.

According to JLS the constant is defined as static final primitive type or string which value is constant in compile time. For example: public static final String PROP_ENTRIES = "entries"; In the JDK 9 there should be an unused CONSTANT_Fieldref in constant pool emitted by compiler which will fix the problem.

  • Missing references from if (compile time false) bloks.
private static final boolean DEBUG = false;
if (DEBUG) {
  • Missing references on types which are just referred in the method bodies (no method call

or field access is done on them) unless you compile with -g:vars. These references are not present due to missing Local Variable Table.

Possible solution

identifier index created from attached sources (no attribution) created when user first time does find usages on the jar with attached sources. Benefits: Fixes missing source patterns Problems: Lots of work on the level of index and refactoring.

If we decide to implement it with binary full index we should notify user about missing features. When the user invokes find usages on a constant or source level annotation, the new scope should not be available and this should be documented in the accompanied help files. As only the method references and field access on non constant fields are reliable we should consider to do the find usages only on them. This will also remove the performance problem as neither method signatures nor code method attributes are parsed. No command line options will be needed.


Find Usages dialog

Scopes for Type


Find Usages results

Results from dependency


Results from JDK

image:FindUsagesJDKsrc.png image:FindUsagesJDKbinary.png

Filters for Dependencies and Binary results

Effort estimation

2 engineers/2 weeks





  • ClassIndex to get Binary Resources from the index.
    • Probably not needed. The ClassIndex already returns resources for binaries which have attached sources for super class, super interfaces. So it can do the same for method calls, field or type references. For binaries with no sources the usage cannot be displayed in method which uses the type, so it does not make much sense.




  1. Indexing binary attached sources by JavaCustomIndexer is no option due to performance impact.
  2. Using binary full index.

Benefits: Already implemented in BinaryAnalyzer, needs to be just enabled.

The performance impact of enabling full binary index on JDK 7 rt.jar:

partial index full index Optimized
Index size: 6,546KB 7,605KB (~+1MB) 6,663KB
creation time 2751ms 5225ms (~100% regression) 5000ms
impact on query time 44ms 48ms (~10% regression) n/a

Performance evaluation

  • Collecting method calls and field access causes no performance degradation.
  • Parsing method signatures introduces performance regression - mostly GC in tenured young (~50%).
  • Collection of local variables needs to parse code attribute which introduces a performance regression (~90%).


Additional information


The branch for Find Usages in Dependencies is here:

Merged into default on June 27 2015

Not logged in. Log in, Register

By use of this website, you agree to the NetBeans Policies and Terms of Use. © 2012, Oracle Corporation and/or its affiliates. Sponsored by Oracle logo