This issue seems to have been created by RT-36565

As of JDK8_20, I experience issue where Map<Tab, ?> (HashMap in my case) sometimes fails to detect it contains a Tab value and thus return null for values attached to this tab.

When going through debugging, the only thing that seems to have been changed in u20 is the inclusion of a new hashCode() method for the Tab class.

My guess is that the problem comes from this method. As of u20, the hashCode() method is as follows:

@Override public int hashCode() {
        int result = selected != null ? selected.hashCode() : 0;
        result = 31 * result + (tabPane != null ? tabPane.hashCode() : 0);
        result = 31 * result + (text != null ? text.hashCode() : 0);
        result = 31 * result + (graphic != null ? graphic.hashCode() : 0);
        result = 31 * result + (content != null ? content.hashCode() : 0);
        return result;
    }

In previous versions the Tab class used the hashCode() method from the Object class and everything was working fine.

Note that I am not able to reproduce this issue in a simple self-contained program. It does however happen in one of my projects.

Here we use a Map<Tab, TabInfo> instance to store some tab configuration values. As each user switch tab, the content of the tab is populated (tabs are initially empty).

   private static class TabInfo {

        public boolean initialized = false;
        public int speciesNumber;
        public Map<Integer, ObservableList<Chart>> speciesChartMap = new HashMap<>();
        public Map<Integer, List<ChartPane>> speciesContainerMap = new HashMap<>();
        public List<? extends ChartHelper> helpers;
    }

    private final Map<Tab, TabInfo> tabInfoMap = new HashMap<>();

[...]

        // Inialize helpers for each chart in display.
        final List<Tab> tabList = new LinkedList<>();
        if (BiomassHelper.canPlot(plotRep)) {
            final Tab biomassTab = new Tab(MOViT.I18N.getString("BIOMASS_CHART_LABEL")); // NOI18N.
            final TabInfo biomassTabInfo = new TabInfo();
            biomassTabInfo.helpers = BiomassHelper.createHelpers(plotRepHelperParameter);
            tabList.add(biomassTab);
            tabInfoMap.put(biomassTab, biomassTabInfo);
        }
        if (ExploitableBiomassHelper.canPlot(plotRep)) {
            final Tab exploitableBiomassTab = new Tab(MOViT.I18N.getString("EXPLOITABLE_POP_BIOMASS_CHART_LABEL")); // NOI18N.
            final TabInfo exploitableBiomassTabInfo = new TabInfo();
            exploitableBiomassTabInfo.helpers = ExploitableBiomassHelper.createHelpers(plotRepHelperParameter);
            tabList.add(exploitableBiomassTab);
            tabInfoMap.put(exploitableBiomassTab, exploitableBiomassTabInfo);
        }
        if (MSYHelper.canPlot(plotRep)) {
            final Tab msyTab = new Tab(MOViT.I18N.getString("MSY_CHART_LABEL")); // NOI18N.
            final TabInfo msyTabInfo = new TabInfo();
            msyTabInfo.helpers = MSYHelper.createHelpers(plotRepHelperParameter);
            tabList.add(msyTab);
            tabInfoMap.put(msyTab, msyTabInfo);
        }
        if (YieldHelper.canPlot(plotRep)) {
            final Tab yieldTab = new Tab(MOViT.I18N.getString("YIELD_CHART_LABEL")); // NOI18N.
            final TabInfo yieldTabInfo = new TabInfo();
            yieldTabInfo.helpers = YieldHelper.createHelpers(plotRepHelperParameter);
            tabList.add(yieldTab);
            tabInfoMap.put(yieldTab, yieldTabInfo);
        }
        if (RecruitmentHelper.canPlot(plotRep)) {
            final Tab recruitmentTab = new Tab(MOViT.I18N.getString("RECRUITMENT_CHART_LABEL")); // NOI18N.
            final TabInfo recruitmentTabInfo = new TabInfo();
            recruitmentTabInfo.helpers = RecruitmentHelper.createHelpers(plotRepHelperParameter);
            tabList.add(recruitmentTab);
            tabInfoMap.put(recruitmentTab, recruitmentTabInfo);
        }
        // Catch.rep
        final Tab catchTab = new Tab(MOViT.I18N.getString("CATCH_CHART_LABEL")); // NOI18N.
        final TabInfo catchTabInfo = new TabInfo();
        catchTabInfo.helpers = Arrays.asList(new org.spc.ofp.project.mfcl.chart.helper.catchrep.CatchHelper(catchRep, plotRep, fisheryNames, timePeriodDates, projectionInfo));
        tabList.add(catchTab);
        tabInfoMap.put(catchTab, catchTabInfo);
        // Frq
        final Tab effortTab = new Tab(MOViT.I18N.getString("EFFORT_CHART_LABEL")); // NOI18N.
        final TabInfo effortTabInfo = new TabInfo();
        effortTabInfo.helpers = Arrays.asList(new EffortHelper1(frq, plotRep, fisheryNames, fisheryEffortMap, projectionInfo));
        tabList.add(effortTab);
        tabInfoMap.put(effortTab, effortTabInfo);
        /////////////////////////////////////////////////////////////

[...]

        tabPane.getTabs().setAll(tabList);

Then here is some diagnostic code that is executed immediately after the map has been populated:

System.out.println(tabInfoMap.size());
        System.out.println("----");
        tabList.forEach(tab -> System.out.printf("%s \"%s\" %d %s", tab, tab.getText(), tab.hashCode(), tabInfoMap.get(tab)).println());
        System.out.println("----");
        tabPane.getTabs().forEach(tab -> System.out.printf("%s \"%s\" %d %s", tab, tab.getText(), tab.hashCode(), tabInfoMap.get(tab)).println());
        System.out.println("----");
        System.out.printf("%s \"%s\" %d %s", effortTab, effortTab.getText(), effortTab.hashCode(), tabInfoMap.get(effortTab)).println();
        System.out.printf("%s \"%s\" %d %s", tabList.get(tabList.size() - 1), tabList.get(tabList.size() - 1).getText(), tabList.get(tabList.size() - 1).hashCode(), tabInfoMap.get(tabList.get(tabList.size() - 1))).println();
        System.out.println("----");
        tabInfoMap.entrySet().forEach(entry -> {
            final Tab tab = entry.getKey();
            final TabInfo tabInfo = entry.getValue();
            System.out.printf("%s \"%s\" %d %s", tab, tab.getText(), tab.hashCode(), tabInfo).println();
            System.out.printf("%b %b %b", tabList.contains(tab), tabPane.getTabs().contains(tab), tabInfoMap.containsKey(tab)).println();
        });
        System.out.println("----");

In u20 the output for this code is as follows:

7
----
javafx.scene.control.Tab@38f726a7 "Biomass" 955721383 null
javafx.scene.control.Tab@896f3700 "Exploitable Pop/Biomass" -1989200128 null
javafx.scene.control.Tab@b246acc7 "MSY" -1303991097 null
javafx.scene.control.Tab@2733aae0 "Yield" 657697504 null
javafx.scene.control.Tab@6f7c2fe9 "Recruitment" 1870409705 null
javafx.scene.control.Tab@895e030 "Catch" 144039984 null
javafx.scene.control.Tab@8142d454 "Effort" -2126326700 null
----
javafx.scene.control.Tab@38f726a7 "Biomass" 955721383 null
javafx.scene.control.Tab@896f3700 "Exploitable Pop/Biomass" -1989200128 null
javafx.scene.control.Tab@b246acc7 "MSY" -1303991097 null
javafx.scene.control.Tab@2733aae0 "Yield" 657697504 null
javafx.scene.control.Tab@6f7c2fe9 "Recruitment" 1870409705 null
javafx.scene.control.Tab@895e030 "Catch" 144039984 null
javafx.scene.control.Tab@8142d454 "Effort" -2126326700 null
----
javafx.scene.control.Tab@8142d454 "Effort" -2126326700 null
javafx.scene.control.Tab@8142d454 "Effort" -2126326700 null
----
javafx.scene.control.Tab@38f726a7 "Biomass" 955721383 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@186e6258
true true false
javafx.scene.control.Tab@895e030 "Catch" 144039984 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@2fff10a4
true true false
javafx.scene.control.Tab@896f3700 "Exploitable Pop/Biomass" -1989200128 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@141dde4b
true true false
javafx.scene.control.Tab@2733aae0 "Yield" 657697504 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@65ab8078
true true false
javafx.scene.control.Tab@8142d454 "Effort" -2126326700 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@ebc4237
true true false
javafx.scene.control.Tab@b246acc7 "MSY" -1303991097 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@59911974
true true false
javafx.scene.control.Tab@6f7c2fe9 "Recruitment" 1870409705 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@23846b8b
true true false


In u11 the output for this code is as follows (everything is working fine):

7
----
javafx.scene.control.Tab@9df514f "Biomass" 165630287 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@3b5fcec0
javafx.scene.control.Tab@234632ea "Exploitable Pop/Biomass" 591803114 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@70f89e4b
javafx.scene.control.Tab@750aeb37 "MSY" 1963649847 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@7b81cecf
javafx.scene.control.Tab@bb2627f "Yield" 196239999 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@38d6a992
javafx.scene.control.Tab@4205b1ad "Recruitment" 1107669421 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@7dba4986
javafx.scene.control.Tab@6d9a664 "Catch" 114927204 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@49048abc
javafx.scene.control.Tab@58f273cb "Effort" 1492284363 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@3c06d2e5
----
javafx.scene.control.Tab@9df514f "Biomass" 165630287 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@3b5fcec0
javafx.scene.control.Tab@234632ea "Exploitable Pop/Biomass" 591803114 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@70f89e4b
javafx.scene.control.Tab@750aeb37 "MSY" 1963649847 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@7b81cecf
javafx.scene.control.Tab@bb2627f "Yield" 196239999 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@38d6a992
javafx.scene.control.Tab@4205b1ad "Recruitment" 1107669421 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@7dba4986
javafx.scene.control.Tab@6d9a664 "Catch" 114927204 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@49048abc
javafx.scene.control.Tab@58f273cb "Effort" 1492284363 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@3c06d2e5
----
javafx.scene.control.Tab@58f273cb "Effort" 1492284363 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@3c06d2e5
javafx.scene.control.Tab@58f273cb "Effort" 1492284363 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@3c06d2e5
----
javafx.scene.control.Tab@9df514f "Biomass" 165630287 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@3b5fcec0
true true true
javafx.scene.control.Tab@4205b1ad "Recruitment" 1107669421 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@7dba4986
true true true
javafx.scene.control.Tab@58f273cb "Effort" 1492284363 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@3c06d2e5
true true true
javafx.scene.control.Tab@234632ea "Exploitable Pop/Biomass" 591803114 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@70f89e4b
true true true
javafx.scene.control.Tab@750aeb37 "MSY" 1963649847 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@7b81cecf
true true true
javafx.scene.control.Tab@bb2627f "Yield" 196239999 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@38d6a992
true true true
javafx.scene.control.Tab@6d9a664 "Catch" 114927204 org.spc.ofp.project.movit.scene.control.review.MFCLReviewPane$TabInfo@49048abc
true true true
----

I will attempt to circumvent the issue by attaching the tabInfo object to the properties of the tab instead of storing it in a separate Map.

Notwithstanding, the issue is pretty much severe and code breaking !