Merge branch '2.3.x'

Closes gh-23000

spring-boot-project/spring-boot-tools/spring-boot-jarmode-layertools/src/main/java/org/springframework/boot/jarmode/layertools/ExtractCommand.java

@@ -27,6 +27,7 @@ import java.util.Map;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipInputStream;
 
+import org.springframework.util.Assert;
 import org.springframework.util.StreamUtils;
 import org.springframework.util.StringUtils;
 
@@ -66,6 +67,8 @@ class ExtractCommand extends Command {
 			}
 			try (ZipInputStream zip = new ZipInputStream(new FileInputStream(this.context.getJarFile()))) {
 				ZipEntry entry = zip.getNextEntry();
+				Assert.state(entry != null, "File '" + this.context.getJarFile().toString()
+						+ "' is not compatible with layertools; ensure jar file is valid and launch script is not enabled");
 				while (entry != null) {
 					if (!entry.isDirectory()) {
 						String layer = this.layers.getLayer(entry);

spring-boot-project/spring-boot-tools/spring-boot-jarmode-layertools/src/test/java/org/springframework/boot/jarmode/layertools/ExtractCommandTests.java

@@ -18,6 +18,7 @@ package org.springframework.boot.jarmode.layertools;
 
 import java.io.File;
 import java.io.FileOutputStream;
+import java.io.FileWriter;
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collections;
@@ -33,6 +34,7 @@ import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
 import static org.mockito.BDDMockito.given;
 
 /**
@@ -99,6 +101,19 @@ class ExtractCommandTests {
 		assertThat(new File(this.extract, "c/c/c.jar")).exists();
 	}
 
+	@Test
+	void runWithJarFileContainingNoEntriesFails() throws IOException {
+		File file = new File(this.temp, "empty.jar");
+		FileWriter writer = new FileWriter(file);
+		writer.write("text");
+		writer.flush();
+		given(this.context.getJarFile()).willReturn(file);
+		given(this.context.getWorkingDir()).willReturn(this.extract);
+		assertThatIllegalStateException()
+				.isThrownBy(() -> this.command.run(Collections.emptyMap(), Collections.emptyList()))
+				.withMessageContaining("not compatible with layertools");
+	}
+
 	private File createJarFile(String name) throws IOException {
 		File file = new File(this.temp, name);
 		try (ZipOutputStream out = new ZipOutputStream(new FileOutputStream(file))) {