Clarify Jackson2ObjectMapper.modules(ToInstall) semantics

Closes gh-22747

Author: sdeleuze

spring-web/src/main/java/org/springframework/http/converter/json/Jackson2ObjectMapperBuilder.java

@@ -497,6 +497,8 @@ public Jackson2ObjectMapperBuilder featuresToDisable(Object... featuresToDisable
 
 	/**
 	 * Specify one or more modules to be registered with the {@link ObjectMapper}.
+	 * Multiple invocations are not additive, the last one defines the modules to
+	 * register.
 	 * <p>Note: If this is set, no finding of modules is going to happen - not by
 	 * Jackson, and not by Spring either (see {@link #findModulesViaServiceLoader}).
 	 * As a consequence, specifying an empty list here will suppress any kind of
@@ -512,6 +514,8 @@ public Jackson2ObjectMapperBuilder modules(Module... modules) {
 
 	/**
 	 * Set a complete list of modules to be registered with the {@link ObjectMapper}.
+	 * Multiple invocations are not additive, the last one defines the modules to
+	 * register.
 	 * <p>Note: If this is set, no finding of modules is going to happen - not by
 	 * Jackson, and not by Spring either (see {@link #findModulesViaServiceLoader}).
 	 * As a consequence, specifying an empty list here will suppress any kind of
@@ -529,6 +533,8 @@ public Jackson2ObjectMapperBuilder modules(List<Module> modules) {
 
 	/**
 	 * Specify one or more modules to be registered with the {@link ObjectMapper}.
+	 * Multiple invocations are not additive, the last one defines the modules
+	 * to register.
 	 * <p>Modules specified here will be registered after
 	 * Spring's autodetection of JSR-310 and Joda-Time, or Jackson's
 	 * finding of modules (see {@link #findModulesViaServiceLoader}),
@@ -545,7 +551,8 @@ public Jackson2ObjectMapperBuilder modulesToInstall(Module... modules) {
 
 	/**
 	 * Specify one or more modules by class to be registered with
-	 * the {@link ObjectMapper}.
+	 * the {@link ObjectMapper}. Multiple invocations are not additive,
+	 * the last one defines the modules to register.
 	 * <p>Modules specified here will be registered after
 	 * Spring's autodetection of JSR-310 and Joda-Time, or Jackson's
 	 * finding of modules (see {@link #findModulesViaServiceLoader}),