工欲善其事，必先利其器 -《论语·卫灵公》
最近在看《代码整洁之道》一书，其示例代码均为 Java 语言所写。虽说编程语言有很多相通的，但作为一名没有写过 Java 的前端，看完大半后发现很难再继续读下去，其中一些思想还是不能理解。加上后面打算再看下《算法》红宝书，正因此，激发了我对 Java 这门语言的兴趣，打算花点时间来入门下 Java 的基础。试了用 Eclipse 和 Intellij 编辑器来写了些练习，发现还是 VSCode 操作顺手。或许有人说 Intellij 很强大，可对于我来说 VSCode 免费、轻量级，优势还是挺明显的，最终也还是选了 VSCode。 写了几天遇到些问题，记录下吧。
扩展安装如果你是为了简单编写和调试 Java 代码，直接安装下面两个扩展就可以直接跑 Java 程序了。
Language Support for Java(TM) by Red Hat Java 语言支持扩展
Debugger for Java Java 调试相关的扩展
若你不满足于此，可以直接安装 Java 全家桶扩展，一扩展搞定所有。
Java Extension Pack Java 主流扩展集合
遇到的问题 1. 怎么更改启动调试快捷键？（由于我使用的 Mac 键盘，每次调试都要同时按 fn + F5 着实影响调试心情）打开 VSCode 快捷键修改设置，路径 Code=>Preferences=>KeyBoard Shortcuts, 在设置的搜索框输入“Run”，找到相应的选项，点击编辑按钮，弹出快捷键录入框，按下你希望设置的组合键就好了
在项目根目录新建 .settings 文件夹(新建完如果在 VSCode 目录里看不到，则看 )，并在此文件夹下新建 org.eclipse.jdt.core.prefs 文件，此文件里面可以加入以下内容：
org.eclipse.jdt.core.prefs eclipse.preferences.version=1 org.eclipse.jdt.core.compiler.annotation.inheritNullAnnotations=disabled org.eclipse.jdt.core.compiler.annotation.missingNonNullByDefaultAnnotation=ignore org.eclipse.jdt.core.compiler.annotation.nonnull=org.eclipse.jdt.annotation.NonNull org.eclipse.jdt.core.compiler.annotation.nonnull.secondary= org.eclipse.jdt.core.compiler.annotation.nonnullbydefault=org.eclipse.jdt.annotation.NonNullByDefault org.eclipse.jdt.core.compiler.annotation.nonnullbydefault.secondary= org.eclipse.jdt.core.compiler.annotation.nullable=org.eclipse.jdt.annotation.Nullable org.eclipse.jdt.core.compiler.annotation.nullable.secondary= org.eclipse.jdt.core.compiler.annotation.nullanalysis=disabled org.eclipse.jdt.core.compiler.problem.APILeak=warning org.eclipse.jdt.core.compiler.problem.annotatedTypeArgumentToUnannotated=info org.eclipse.jdt.core.compiler.problem.annotationSuperInterface=warning org.eclipse.jdt.core.compiler.problem.autoboxing=ignore org.eclipse.jdt.core.compiler.problem.comparingIdentical=warning org.eclipse.jdt.core.compiler.problem.deadCode=warning org.eclipse.jdt.core.compiler.problem.deprecation=warning org.eclipse.jdt.core.compiler.problem.deprecationInDeprecatedCode=disabled org.eclipse.jdt.core.compiler.problem.deprecationWhenOverridingDeprecatedMethod=disabled org.eclipse.jdt.core.compiler.problem.discouragedReference=warning org.eclipse.jdt.core.compiler.problem.emptyStatement=ignore org.eclipse.jdt.core.compiler.problem.explicitlyClosedAutoCloseable=ignore org.eclipse.jdt.core.compiler.problem.fallthroughCase=ignore org.eclipse.jdt.core.compiler.problem.fatalOptionalError=disabled org.eclipse.jdt.core.compiler.problem.fieldHiding=ignore org.eclipse.jdt.core.compiler.problem.finalParameterBound=warning org.eclipse.jdt.core.compiler.problem.finallyBlockNotCompletingNormally=warning org.eclipse.jdt.core.compiler.problem.forbiddenReference=error org.eclipse.jdt.core.compiler.problem.hiddenCatchBlock=warning org.eclipse.jdt.core.compiler.problem.includeNullInfoFromAsserts=disabled org.eclipse.jdt.core.compiler.problem.incompatibleNonInheritedInterfaceMethod=warning org.eclipse.jdt.core.compiler.problem.incompleteEnumSwitch=warning org.eclipse.jdt.core.compiler.problem.indirectStaticAccess=ignore org.eclipse.jdt.core.compiler.problem.localVariableHiding=ignore org.eclipse.jdt.core.compiler.problem.methodWithConstructorName=warning org.eclipse.jdt.core.compiler.problem.missingDefaultCase=ignore org.eclipse.jdt.core.compiler.problem.missingDeprecatedAnnotation=ignore org.eclipse.jdt.core.compiler.problem.missingEnumCaseDespiteDefault=disabled org.eclipse.jdt.core.compiler.problem.missingHashCodeMethod=ignore org.eclipse.jdt.core.compiler.problem.missingOverrideAnnotation=ignore org.eclipse.jdt.core.compiler.problem.missingOverrideAnnotationForInterfaceMethodImplementation=enabled org.eclipse.jdt.core.compiler.problem.missingSerialVersion=warning org.eclipse.jdt.core.compiler.problem.missingSynchronizedOnInheritedMethod=ignore org.eclipse.jdt.core.compiler.problem.noEffectAssignment=warning org.eclipse.jdt.core.compiler.problem.noImplicitStringConversion=warning org.eclipse.jdt.core.compiler.problem.nonExternalizedStringLiteral=ignore org.eclipse.jdt.core.compiler.problem.nonnullParameterAnnotationDropped=warning org.eclipse.jdt.core.compiler.problem.nonnullTypeVariableFromLegacyInvocation=warning org.eclipse.jdt.core.compiler.problem.nullAnnotationInferenceConflict=error org.eclipse.jdt.core.compiler.problem.nullReference=warning org.eclipse.jdt.core.compiler.problem.nullSpecViolation=error org.eclipse.jdt.core.compiler.problem.nullUncheckedConversion=warning org.eclipse.jdt.core.compiler.problem.overridingPackageDefaultMethod=warning org.eclipse.jdt.core.compiler.problem.parameterAssignment=ignore org.eclipse.jdt.core.compiler.problem.pessimisticNullAnalysisForFreeTypeVariables=warning org.eclipse.jdt.core.compiler.problem.possibleAccidentalBooleanAssignment=ignore org.eclipse.jdt.core.compiler.problem.potentialNullReference=ignore org.eclipse.jdt.core.compiler.problem.potentiallyUnclosedCloseable=ignore org.eclipse.jdt.core.compiler.problem.rawTypeReference=warning org.eclipse.jdt.core.compiler.problem.redundantNullAnnotation=warning org.eclipse.jdt.core.compiler.problem.redundantNullCheck=ignore org.eclipse.jdt.core.compiler.problem.redundantSpecificationOfTypeArguments=ignore org.eclipse.jdt.core.compiler.problem.redundantSuperinterface=ignore org.eclipse.jdt.core.compiler.problem.reportMethodCanBePotentiallyStatic=ignore org.eclipse.jdt.core.compiler.problem.reportMethodCanBeStatic=ignore org.eclipse.jdt.core.compiler.problem.specialParameterHidingField=disabled org.eclipse.jdt.core.compiler.problem.staticAccessReceiver=warning org.eclipse.jdt.core.compiler.problem.suppressOptionalErrors=disabled org.eclipse.jdt.core.compiler.problem.suppressWarnings=enabled org.eclipse.jdt.core.compiler.problem.suppressWarningsNotFullyAnalysed=info org.eclipse.jdt.core.compiler.problem.syntacticNullAnalysisForFields=disabled org.eclipse.jdt.core.compiler.problem.syntheticAccessEmulation=ignore org.eclipse.jdt.core.compiler.problem.terminalDeprecation=warning org.eclipse.jdt.core.compiler.problem.typeParameterHiding=warning org.eclipse.jdt.core.compiler.problem.unavoidableGenericTypeProblems=enabled org.eclipse.jdt.core.compiler.problem.uncheckedTypeOperation=warning org.eclipse.jdt.core.compiler.problem.unclosedCloseable=warning org.eclipse.jdt.core.compiler.problem.undocumentedEmptyBlock=ignore org.eclipse.jdt.core.compiler.problem.unhandledWarningToken=warning org.eclipse.jdt.core.compiler.problem.unlikelyCollectionMethodArgumentType=warning org.eclipse.jdt.core.compiler.problem.unlikelyCollectionMethodArgumentTypeStrict=disabled org.eclipse.jdt.core.compiler.problem.unlikelyEqualsArgumentType=info org.eclipse.jdt.core.compiler.problem.unnecessaryElse=ignore org.eclipse.jdt.core.compiler.problem.unnecessaryTypeCheck=ignore org.eclipse.jdt.core.compiler.problem.unqualifiedFieldAccess=ignore org.eclipse.jdt.core.compiler.problem.unstableAutoModuleName=warning org.eclipse.jdt.core.compiler.problem.unusedDeclaredThrownException=ignore org.eclipse.jdt.core.compiler.problem.unusedDeclaredThrownExceptionExemptExceptionAndThrowable=enabled org.eclipse.jdt.core.compiler.problem.unusedDeclaredThrownExceptionIncludeDocCommentReference=enabled org.eclipse.jdt.core.compiler.problem.unusedDeclaredThrownExceptionWhenOverriding=disabled org.eclipse.jdt.core.compiler.problem.unusedExceptionParameter=ignore org.eclipse.jdt.core.compiler.problem.unusedImport=ignore org.eclipse.jdt.core.compiler.problem.unusedLabel=warning org.eclipse.jdt.core.compiler.problem.unusedLocal=ignore org.eclipse.jdt.core.compiler.problem.unusedObjectAllocation=ignore org.eclipse.jdt.core.compiler.problem.unusedParameter=ignore org.eclipse.jdt.core.compiler.problem.unusedParameterIncludeDocCommentReference=enabled org.eclipse.jdt.core.compiler.problem.unusedParameterWhenImplementingAbstract=disabled org.eclipse.jdt.core.compiler.problem.unusedParameterWhenOverridingConcrete=disabled org.eclipse.jdt.core.compiler.problem.unusedPrivateMember=ignore org.eclipse.jdt.core.compiler.problem.unusedTypeParameter=ignore org.eclipse.jdt.core.compiler.problem.unusedWarningToken=warning org.eclipse.jdt.core.compiler.problem.varargsArgumentNeedCast=warning 3. 新建 .settings 文件夹后看不到？在 VSCode 设置里加入下面配置就好（Command + , 打开配置文件）
{ "files.exclude": { "**/.settings": false, }, }