Remove JSR-330 configuration annotations

Replace JSR-330 validation annotations from all internal
`@ConfigurationProperties` classes with standard Asserts.

Prior to this commit validation of our own configuration properties
would only occur when the user happens to have compliant JSR-330
implementation on their classpath.

See gh-7579

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/flyway/FlywayProperties.java

@@ -37,10 +37,11 @@ import org.springframework.boot.context.properties.ConfigurationProperties;
 public class FlywayProperties {
 
 	/**
-	 * Locations of migrations scripts. Can contain the special "{vendor}" placeholder
-	 * to use vendor-specific locations.
+	 * Locations of migrations scripts. Can contain the special "{vendor}" placeholder to
+	 * use vendor-specific locations.
 	 */
-	private List<String> locations = new ArrayList<String>(Collections.singletonList("db/migration"));
+	private List<String> locations = new ArrayList<String>(
+			Collections.singletonList("db/migration"));
 
 	/**
 	 * Check that migration scripts location exists.

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/h2/H2ConsoleProperties.java

@@ -16,10 +16,10 @@
 
 package org.springframework.boot.autoconfigure.h2;
 
-import javax.validation.constraints.NotNull;
-import javax.validation.constraints.Pattern;
+import javax.annotation.PostConstruct;
 
 import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.util.Assert;
 
 /**
  * Configuration properties for H2's console.
@@ -35,8 +35,6 @@ public class H2ConsoleProperties {
 	/**
 	 * Path at which the console will be available.
 	 */
-	@NotNull
-	@Pattern(regexp = "/[^?#]*", message = "Path must start with /")
 	private String path = "/h2-console";
 
 	/**
@@ -46,6 +44,13 @@ public class H2ConsoleProperties {
 
 	private final Settings settings = new Settings();
 
+	@PostConstruct
+	private void validate() {
+		Assert.notNull(this.path, "Path must not be null");
+		Assert.isTrue(this.path.length() == 0 || this.path.startsWith("/"),
+				"Path must start with / or be empty");
+	}
+
 	public String getPath() {
 		return this.path;
 	}

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/liquibase/LiquibaseProperties.java

@@ -19,11 +19,12 @@ package org.springframework.boot.autoconfigure.liquibase;
 import java.io.File;
 import java.util.Map;
 
-import javax.validation.constraints.NotNull;
+import javax.annotation.PostConstruct;
 
 import liquibase.integration.spring.SpringLiquibase;
 
 import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.util.Assert;
 
 /**
  * Configuration properties to configure {@link SpringLiquibase}.
@@ -37,7 +38,6 @@ public class LiquibaseProperties {
 	/**
 	 * Change log configuration path.
 	 */
-	@NotNull
 	private String changeLog = "classpath:/db/changelog/db.changelog-master.yaml";
 
 	/**
@@ -96,6 +96,11 @@ public class LiquibaseProperties {
 	 */
 	private File rollbackFile;
 
+	@PostConstruct
+	private void validate() {
+		Assert.notNull(this.changeLog, "ChangeLog must not be null");
+	}
+
 	public String getChangeLog() {
 		return this.changeLog;
 	}

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/ServerProperties.java

@@ -26,11 +26,11 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
+import javax.annotation.PostConstruct;
 import javax.servlet.ServletContext;
 import javax.servlet.ServletException;
 import javax.servlet.SessionCookieConfig;
 import javax.servlet.SessionTrackingMode;
-import javax.validation.constraints.NotNull;
 
 import io.undertow.Undertow.Builder;
 import io.undertow.UndertowOptions;
@@ -74,6 +74,7 @@ import org.springframework.boot.web.servlet.ServletContextInitializer;
 import org.springframework.context.EnvironmentAware;
 import org.springframework.core.Ordered;
 import org.springframework.core.env.Environment;
+import org.springframework.util.Assert;
 import org.springframework.util.ObjectUtils;
 import org.springframework.util.StringUtils;
 
@@ -122,7 +123,6 @@ public class ServerProperties
 	/**
 	 * Path of the main dispatcher servlet.
 	 */
-	@NotNull
 	private String servletPath = "/";
 
 	/**
@@ -176,6 +176,11 @@ public class ServerProperties
 
 	private Environment environment;
 
+	@PostConstruct
+	private void validate() {
+		Assert.notNull(this.servletPath, "ServletPath must not be null");
+	}
+
 	@Override
 	public int getOrder() {
 		return 0;

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/webservices/WebServicesProperties.java

@@ -19,10 +19,10 @@ package org.springframework.boot.autoconfigure.webservices;
 import java.util.HashMap;
 import java.util.Map;
 
-import javax.validation.constraints.NotNull;
-import javax.validation.constraints.Pattern;
+import javax.annotation.PostConstruct;
 
 import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.util.Assert;
 
 /**
  * {@link ConfigurationProperties} for Spring Web Services.
@@ -37,12 +37,17 @@ public class WebServicesProperties {
 	/**
 	 * Path that serves as the base URI for the services.
 	 */
-	@NotNull
-	@Pattern(regexp = "/[^?#]*", message = "Path must start with /")
 	private String path = "/services";
 
 	private final Servlet servlet = new Servlet();
 
+	@PostConstruct
+	private void validate() {
+		Assert.notNull(this.path, "Path must not be null");
+		Assert.isTrue(this.path.length() == 0 || this.path.startsWith("/"),
+				"Path must start with / or be empty");
+	}
+
 	public String getPath() {
 		return this.path;
 	}