SONARJAVA-5292 Create rule S7183: @InitBinder methods should have void return type (#4616)

rules/S7183/java/metadata.json

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+{
+  "title": "@InitBinder methods should have void return type",
+  "type": "CODE_SMELL",
+  "status": "ready",
+  "remediation": {
+    "func": "Constant\/Issue",
+    "constantCost": "5min"
+  },
+  "tags": [
+    "spring"
+  ],
+  "defaultSeverity": "Major",
+  "ruleSpecification": "RSPEC-7183",
+  "sqKey": "S7183",
+  "scope": "All",
+  "defaultQualityProfiles": ["Sonar way"],
+  "quickfix": "unknown",
+  "code": {
+    "impacts": {
+      "RELIABILITY": "MEDIUM",
+      "SECURITY": "LOW"
+    },
+    "attribute": "LOGICAL"
+  }
+}

rules/S7183/java/rule.adoc

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+== Why is this an issue?
+
+Spring provides the `@InitBinder` annotation to initialize a `WebDataBinder` instance for controllers.
+This is useful to bind request parameters to a model object, and to plug converters and formatters into this process.
+
+Methods annotated with `@InitBinder` must not have a return value, otherwise the controller containing them will throw an exception when invoked.
+
+This rule raises an issue when a method annotated with `@InitBinder` does not have a `void` return type
+
+== How to fix it
+
+=== Code examples
+
+==== Noncompliant code example
+
+[source,java,diff-id=1,diff-type=noncompliant]
+----
+@Controller
+public class MyController {
+
+	@InitBinder 
+	public String initBinder(WebDataBinder binder) { // Non compliant, make the @InitBinder method return void
+		SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
+		dateFormat.setLenient(false);
+		binder.registerCustomEditor(Date.class, new CustomDateEditor(dateFormat, false));
+        return "OK";
+	}
+
+	// ...
+}
+----
+
+==== Compliant solution
+
+[source,java,diff-id=1,diff-type=compliant]
+----
+@Controller
+public class MyController {
+
+	@InitBinder 
+	public void initBinder(WebDataBinder binder) {
+		SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
+		dateFormat.setLenient(false);
+		binder.registerCustomEditor(Date.class, new CustomDateEditor(dateFormat, false));
+	}
+
+	// ...
+}
+----
+
+== Resources
+=== Documentation
+
+* Spring api - https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/web/bind/annotation/InitBinder.html[@InitBinder api]
+* String documentation - https://docs.spring.io/spring-framework/reference/web/webmvc/mvc-controller/ann-initbinder.html[@InitBinder docs]

rules/S7183/metadata.json

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+{
+}