Replace System.getProperties().remove(x) with System.clearProperty(x)

This commit migrates to the not-so-new System.clearProperty() method
introduced in Java 1.5.

spring-context/src/jmh/java/org/springframework/context/expression/ApplicationContextExpressionBenchmark.java

@@ -57,8 +57,8 @@ public class ApplicationContextExpressionBenchmark {
 
 		@TearDown
 		public void teardown() {
-			System.getProperties().remove("country");
-			System.getProperties().remove("name");
+			System.clearProperty("country");
+			System.clearProperty("name");
 		}
 	}
 

spring-context/src/test/java/org/springframework/context/config/ContextNamespaceHandlerTests.java

@@ -43,7 +43,7 @@ class ContextNamespaceHandlerTests {
 
 	@AfterEach
 	void tearDown() {
-		System.getProperties().remove("foo");
+		System.clearProperty("foo");
 	}
 
 

spring-context/src/test/java/org/springframework/context/expression/ApplicationContextExpressionTests.java

@@ -196,7 +196,7 @@ class ApplicationContextExpressionTests {
 			assertThat(tb6.tb).isSameAs(tb0);
 		}
 		finally {
-			System.getProperties().remove("country");
+			System.clearProperty("country");
 		}
 	}
 
@@ -230,8 +230,8 @@ class ApplicationContextExpressionTests {
 			assertThat(tb.getCountry2()).isEqualTo("-UK2-");
 		}
 		finally {
-			System.getProperties().remove("name");
-			System.getProperties().remove("country");
+			System.clearProperty("name");
+			System.clearProperty("country");
 		}
 	}
 
@@ -264,7 +264,7 @@ class ApplicationContextExpressionTests {
 			assertThat(FileCopyUtils.copyToString(resourceInjectionBean.reader)).isEqualTo(FileCopyUtils.copyToString(new EncodedResource(resource).getReader()));
 		}
 		finally {
-			System.getProperties().remove("logfile");
+			System.clearProperty("logfile");
 		}
 	}
 

spring-core/src/test/java/org/springframework/core/io/ResourceEditorTests.java

@@ -73,7 +73,7 @@ class ResourceEditorTests {
 			assertThat(resolved.getFilename()).isEqualTo("foo");
 		}
 		finally {
-			System.getProperties().remove("test.prop");
+			System.clearProperty("test.prop");
 		}
 	}
 
@@ -87,7 +87,7 @@ class ResourceEditorTests {
 			assertThat(resolved.getFilename()).isEqualTo("foo-${bar}");
 		}
 		finally {
-			System.getProperties().remove("test.prop");
+			System.clearProperty("test.prop");
 		}
 	}
 
@@ -102,7 +102,7 @@ class ResourceEditorTests {
 			});
 		}
 		finally {
-			System.getProperties().remove("test.prop");
+			System.clearProperty("test.prop");
 		}
 	}
 

spring-core/src/test/java/org/springframework/core/io/support/ResourceArrayPropertyEditorTests.java

@@ -70,7 +70,7 @@ class ResourceArrayPropertyEditorTests {
 			assertThat(resources[0].getFilename()).isEqualTo("foo");
 		}
 		finally {
-			System.getProperties().remove("test.prop");
+			System.clearProperty("test.prop");
 		}
 	}
 
@@ -85,7 +85,7 @@ class ResourceArrayPropertyEditorTests {
 					editor.setAsText("${test.prop}-${bar}"));
 		}
 		finally {
-			System.getProperties().remove("test.prop");
+			System.clearProperty("test.prop");
 		}
 	}
 

spring-core/src/test/java/org/springframework/util/SystemPropertyUtilsTests.java

@@ -37,7 +37,7 @@ class SystemPropertyUtilsTests {
 			assertThat(resolved).isEqualTo("bar");
 		}
 		finally {
-			System.getProperties().remove("test.prop");
+			System.clearProperty("test.prop");
 		}
 	}
 
@@ -49,7 +49,7 @@ class SystemPropertyUtilsTests {
 			assertThat(resolved).isEqualTo("bar");
 		}
 		finally {
-			System.getProperties().remove("test.prop");
+			System.clearProperty("test.prop");
 		}
 	}
 
@@ -61,7 +61,7 @@ class SystemPropertyUtilsTests {
 			assertThat(resolved).isEqualTo("bar");
 		}
 		finally {
-			System.getProperties().remove("test.prop");
+			System.clearProperty("test.prop");
 		}
 	}
 
@@ -73,7 +73,7 @@ class SystemPropertyUtilsTests {
 			assertThat(resolved).isEqualTo("bar");
 		}
 		finally {
-			System.getProperties().remove("test.prop");
+			System.clearProperty("test.prop");
 		}
 	}
 
@@ -122,8 +122,8 @@ class SystemPropertyUtilsTests {
 			assertThat(resolved).isEqualTo("foo=baz");
 		}
 		finally {
-			System.getProperties().remove("test.prop");
-			System.getProperties().remove("bar");
+			System.clearProperty("test.prop");
+			System.clearProperty("bar");
 		}
 	}
 

spring-web/src/main/java/org/springframework/web/util/WebUtils.java

@@ -264,7 +264,7 @@ public abstract class WebUtils {
 		Assert.notNull(servletContext, "ServletContext must not be null");
 		String param = servletContext.getInitParameter(WEB_APP_ROOT_KEY_PARAM);
 		String key = (param != null ? param : DEFAULT_WEB_APP_ROOT_KEY);
-		System.getProperties().remove(key);
+		System.clearProperty(key);
 	}
 
 	/**