問題１完了しました。

javalesson1/.classpath

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-21">
+		<attributes>
+			<attribute name="module" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>

javalesson1/.gitignore

@@ -0,0 +1 @@
+/bin/

javalesson1/.project

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+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>javalesson1</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+	</natures>
+</projectDescription>

javalesson1/.settings/org.eclipse.core.resources.prefs

@@ -0,0 +1,2 @@
+eclipse.preferences.version=1
+encoding/<project>=UTF-8

javalesson1/.settings/org.eclipse.jdt.core.prefs

@@ -0,0 +1,11 @@
+eclipse.preferences.version=1
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=21
+org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
+org.eclipse.jdt.core.compiler.compliance=21
+org.eclipse.jdt.core.compiler.debug.lineNumber=generate
+org.eclipse.jdt.core.compiler.debug.localVariable=generate
+org.eclipse.jdt.core.compiler.debug.sourceFile=generate
+org.eclipse.jdt.core.compiler.problem.enablePreviewFeatures=disabled
+org.eclipse.jdt.core.compiler.problem.reportPreviewFeatures=warning
+org.eclipse.jdt.core.compiler.release=enabled
+org.eclipse.jdt.core.compiler.source=21

javalesson1/src/javalesson1/StringCheck.java

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+package javalesson1;
+
+public class StringCheck {
+	public static void main(String[] args) {
+		String[] classNames= new String[4];
+		classNames[0]="いまなにしている？";
+		classNames[1]="何も入力されていません";
+	    classNames[2]="投稿文が長すぎます";
+	    classNames[3]="↓↓↓↓↓↓　投稿されました　↓↓↓↓↓↓";
+	    System.out.println(classNames[0]);
+	    System.out.println(classNames[1]);
+	    System.out.println(classNames[2]);
+	    System.out.println(classNames[3]);
+}
+	}