fix for eclipse-ee4j#4082

Signed-off-by: Maxim Nesen <[email protected]>

core-common/src/main/java/org/glassfish/jersey/model/internal/ComponentBag.java

@@ -18,6 +18,7 @@
 
 import java.lang.annotation.Annotation;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.IdentityHashMap;
 import java.util.Iterator;
 import java.util.LinkedHashSet;
@@ -481,18 +482,19 @@ public static ContractProvider modelFor(final Class<?> componentClass) {
      *                        (if any).
      * @param contractMap     map of contracts and their binding priorities. If {@code null}, the contracts will
      *                        gathered by introspecting the component class. Content of the contract map
-     *                        may be modified during the registration processing.
+     *                        may not be modified during the registration processing.
      * @param modelEnhancer   custom contract provider model enhancer.
      * @return contract provider model for the class.
      */
     private static ContractProvider modelFor(final Class<?> componentClass,
                                              final int defaultPriority,
                                              final Map<Class<?>, Integer> contractMap,
                                              final Inflector<ContractProvider.Builder, ContractProvider> modelEnhancer) {
-        Map<Class<?>, Integer> contracts = contractMap;
-        if (contracts == null) { // introspect
+        Map<Class<?>, Integer> contracts;
+        if (contractMap == null) { // introspect
             contracts = asMap(Providers.getProviderContracts(componentClass));
         } else { // filter custom contracts
+            contracts = new HashMap<>(contractMap);
             final Iterator<Class<?>> it = contracts.keySet().iterator();
             while (it.hasNext()) {
                 final Class<?> contract = it.next();

core-common/src/main/java/org/glassfish/jersey/spi/CustomConfiguration.java

@@ -0,0 +1,17 @@
+package org.glassfish.jersey.spi;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Annotates custom configuration provided by external users.
+ */
+
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.TYPE)
+@Documented
+public @interface CustomConfiguration {
+}