Switching Logback's file logging charset to UTF-8

Aligns the file charset between Log4j2 and Logback.

Prior to this commit, there was an inconsistency between the two:
Log4j2 used UTF-8, while Logback used Charset.defaultCharset(),
which is platform-dependent.

Signed-off-by: Dmytro Nosan <[email protected]>

Author: nosan

core/spring-boot/src/main/java/org/springframework/boot/logging/logback/LogbackLoggingSystemProperties.java

@@ -17,7 +17,6 @@
 package org.springframework.boot.logging.logback;
 
 import java.io.Console;
-import java.nio.charset.Charset;
 import java.util.function.BiConsumer;
 import java.util.function.Function;
 
@@ -78,11 +77,6 @@ public LogbackLoggingSystemProperties(Environment environment,
 		return super.getConsole();
 	}
 
-	@Override
-	protected Charset getDefaultFileCharset() {
-		return Charset.defaultCharset();
-	}
-
 	@Override
 	protected void apply(@Nullable LogFile logFile, PropertyResolver resolver) {
 		super.apply(logFile, resolver);

core/spring-boot/src/test/java/org/springframework/boot/logging/logback/LogbackLoggingSystemPropertiesTests.java

@@ -131,10 +131,10 @@ void consoleCharsetWhenNoPropertyUsesSystemConsoleCharsetWhenAvailable() {
 	}
 
 	@Test
-	void fileCharsetWhenNoPropertyUsesDefault() {
+	void fileCharsetWhenNoPropertyUsesUtf8() {
 		new LoggingSystemProperties(new MockEnvironment()).apply(null);
 		assertThat(System.getProperty(LoggingSystemProperty.FILE_CHARSET.getEnvironmentVariableName()))
-			.isEqualTo(Charset.defaultCharset().name());
+			.isEqualTo(StandardCharsets.UTF_8.name());
 	}
 
 }