Minor code Improvements

src/main/java/com/cloudbees/jenkins/plugins/customtools/CustomTool.java

@@ -198,7 +198,7 @@ public void check() throws CustomToolException {
      * @since 0.3
      */
     public @Nonnull List<LabelSpecifics> getAppliedSpecifics(@Nonnull Node node) {
-        List<LabelSpecifics> out = new LinkedList<LabelSpecifics>();
+        List<LabelSpecifics> out = new LinkedList<>();
         if (labelSpecifics != null) {
             for (LabelSpecifics spec : labelSpecifics) {
                 if (spec.appliesTo(node)) {
@@ -283,7 +283,7 @@ public PathsList invoke(File f, VirtualChannel channel)
                     throws IOException, InterruptedException {           
 
                 // Construct output paths
-                List<String> items = new LinkedList<String>();
+                List<String> items = new LinkedList<>();
                 if (exportedPaths != null) {
                     parseLists(exportedPaths, items);
                 }
@@ -295,7 +295,7 @@ public PathsList invoke(File f, VirtualChannel channel)
                 }
 
                 // Resolve exported paths
-                List<String> outList = new LinkedList<String>();
+                List<String> outList = new LinkedList<>();
                 for (String item : items) {    
                     File file = new File(item);
                     if (!file.isAbsolute()) {

src/main/java/com/cloudbees/jenkins/plugins/customtools/CustomToolInstallWrapper.java

@@ -155,7 +155,7 @@ public Launcher decorateLauncher(AbstractBuild build, final Launcher launcher,
         final EnvVars versions = new EnvVars();
 
         final PathsList paths = new PathsList();
-        final List<EnvVariablesInjector> additionalVarInjectors = new LinkedList<EnvVariablesInjector>();
+        final List<EnvVariablesInjector> additionalVarInjectors = new LinkedList<>();
 
         // Handle multi-configuration build
         if (build instanceof MatrixBuild) {  

src/main/java/com/synopsys/arc/jenkinsci/plugins/customtools/EnvVariablesInjector.java

@@ -142,11 +142,11 @@ public void injectVariables(@Nonnull EnvVars target) throws IOException {
             //TODO: check overrides
             //TODO: check lists 
             //TODO: substitute, check, etc.
-            
-            //Substitute current envValue
-            String replacedValue = target.containsKey(envName) ? target.get(envName) : "";        
-            String newEnvValue=envValue.replace("${"+envName+"}", replacedValue);                       
-            
+
+            // Substitute current envValue
+            String replacedValue = target.getOrDefault(envName, "");
+            String newEnvValue = envValue.replace("${" + envName + "}", replacedValue);
+
             target.put(envName, newEnvValue);
         }
     }  

src/main/java/com/synopsys/arc/jenkinsci/plugins/customtools/PathsList.java

@@ -35,7 +35,7 @@ public class PathsList implements Serializable {
     public @CheckForNull String pathSeparator;
     public @CheckForNull String separator;
 
-    public static final PathsList EMPTY = new PathsList(new LinkedList<String>(), null);
+    public static final PathsList EMPTY = new PathsList(new LinkedList<>(), null);
 
     /**
      * Constructor. Sets system's default separator and pathSeparator
@@ -50,13 +50,13 @@ public PathsList(@Nonnull Collection<String> paths, @CheckForNull String homeDir
      * Empty constructor. doesn't set pathSeparator and separator
      */
     public PathsList() {
-        this(new LinkedList<String>(), null, null, null);
+        this(new LinkedList<>(), null, null, null);
     }
 
     public PathsList(@Nonnull Collection<String> paths, 
             @CheckForNull String pathSeparator, @CheckForNull String separator, 
             @CheckForNull String homeDir) {
-        this.paths = new ArrayList<String>(paths);
+        this.paths = new ArrayList<>(paths);
         this.pathSeparator = pathSeparator;
         this.separator = separator;
         this.homeDir = homeDir;

src/main/java/com/synopsys/arc/jenkinsci/plugins/customtools/versions/ToolVersionHelper.java

@@ -57,7 +57,7 @@ public static ExtendedChoiceParameterDefinition getVersionDescr(String toolName)
      */
     public static @Nonnull List<CustomTool> getAllVersionedTools() {
         CustomTool.DescriptorImpl tools = ToolInstallation.all().get(CustomTool.DescriptorImpl.class);
-        List<CustomTool> res = new LinkedList<CustomTool>();
+        List<CustomTool> res = new LinkedList<>();
         if (tools != null ) {
             for (CustomTool tool : tools.getInstallations()) {
                 if (tool.hasVersions()) {

src/main/java/jenkins/plugins/customtools/util/envvars/VariablesSubstitutionHelper.java

@@ -99,7 +99,7 @@ public String resolveVariable(@CheckForNull String inputValue, @Nonnull Node nod
      */
     private String substituteNodeProperty(@CheckForNull String macroString, @CheckForNull NodeProperty<?> property) {
         // Get environment variables
-        if (property != null && property instanceof EnvironmentVariablesNodeProperty) {
+        if (property instanceof EnvironmentVariablesNodeProperty) {
            EnvironmentVariablesNodeProperty prop = (EnvironmentVariablesNodeProperty)property;
            return resolveVariable(macroString, prop.getEnvVars());
         }

src/test/java/com/cloudbees/jenkins/plugins/customtools/CustomToolInstallWrapperTest.java

@@ -51,7 +51,7 @@ public class CustomToolInstallWrapperTest {
      */
     @Test
     public void testNestedWrapper() throws Exception {
-        List<BuildWrapper> wrappers = new ArrayList<BuildWrapper>(2);
+        List<BuildWrapper> wrappers = new ArrayList<>(2);
         wrappers.add(new StubWrapper());
         wrappers.add(setupCustomToolsWrapper());
         nestedWrapperTestImpl(wrappers, true);
@@ -63,7 +63,7 @@ public void testNestedWrapper() throws Exception {
      */
     @Test
     public void testNestedWrapperReverse() throws Exception {
-        List<BuildWrapper> wrappers = new ArrayList<BuildWrapper>(2);
+        List<BuildWrapper> wrappers = new ArrayList<>(2);
         wrappers.add(setupCustomToolsWrapper());
         wrappers.add(new StubWrapper());       
         nestedWrapperTestImpl(wrappers, true);
@@ -79,7 +79,7 @@ public void testNestedWrapperReverse() throws Exception {
     @Test
     @Issue("JENKINS-19506")
     public void testNestedLauncherCalls() throws Exception {
-        List<BuildWrapper> wrappers = new ArrayList<BuildWrapper>(2);
+        List<BuildWrapper> wrappers = new ArrayList<>(2);
         wrappers.add(new CommandCallerInstaller());  
         wrappers.add(setupCustomToolsWrapper());     
         nestedWrapperTestImpl(wrappers, false);
@@ -88,7 +88,7 @@ public void testNestedLauncherCalls() throws Exception {
     @Test
     @Issue("JENKINS-20560")
     public void testEmptyToolsList() throws Exception {
-        List<BuildWrapper> wrappers = new ArrayList<BuildWrapper>(0); 
+        List<BuildWrapper> wrappers = new ArrayList<>(0);
         wrappers.add(new CommandCallerInstaller());
         wrappers.add(new CustomToolInstallWrapper(null, MulticonfigWrapperOptions.DEFAULT, false));
         nestedWrapperTestImpl(wrappers, false);

src/test/java/com/cloudbees/jenkins/plugins/customtools/CustomToolInstallerTest.java

@@ -110,22 +110,22 @@ public void testAdditionalVars() throws Exception {
     }
 
     public static CustomTool createTool(String name) throws IOException {
-        List<ToolInstaller> installers = new ArrayList<ToolInstaller>();
+        List<ToolInstaller> installers = new ArrayList<>();
         installers.add(new CommandInstaller(null, "ln -s `which true` mytrue",
                 "./"));
 
-        List<ToolProperty<ToolInstallation>> properties = new ArrayList<ToolProperty<ToolInstallation>>();
+        List<ToolProperty<ToolInstallation>> properties = new ArrayList<>();
         properties.add(new InstallSourceProperty(installers));
 
         return new CustomTool("MyTrue", null, properties, "./", null, ToolVersionConfig.DEFAULT, null);
     }
 
     //TODO: refactor and generalize
     private CustomTool createEnvPrinterTool(String name, LabelSpecifics[] specifics, String additionalVars) throws IOException {
-        List<ToolInstaller> installers = new ArrayList<ToolInstaller>();
+        List<ToolInstaller> installers = new ArrayList<>();
         installers.add(new CommandInstaller(null, "ln -s `which true` mytrue", "./"));
 
-        List<ToolProperty<ToolInstallation>> properties = new ArrayList<ToolProperty<ToolInstallation>>();
+        List<ToolProperty<ToolInstallation>> properties = new ArrayList<>();
         properties.add(new InstallSourceProperty(installers));
 
         return new CustomTool(name, null, properties, "./", specifics, ToolVersionConfig.DEFAULT, additionalVars);

src/test/java/com/synopsys/arc/jenkins/plugins/customtools/versions/ToolVersionParameterDefinitionTest.java

@@ -70,9 +70,9 @@ public class ToolVersionParameterDefinitionTest {
 
     private void setupVersionedTool() throws Exception {
         CustomTool.DescriptorImpl tools = j.jenkins.getDescriptorByType(CustomTool.DescriptorImpl.class);
-        List<ToolInstaller> installers = new ArrayList<ToolInstaller>();
+        List<ToolInstaller> installers = new ArrayList<>();
         installers.add(new CommandInstaller(null, "ln -s `which true` mytrue", "./"));
-        List<ToolProperty<ToolInstallation>> properties = new ArrayList<ToolProperty<ToolInstallation>>();
+        List<ToolProperty<ToolInstallation>> properties = new ArrayList<>();
         properties.add(new InstallSourceProperty(installers));
         CustomTool installation = new CustomTool(TEST_TOOL_NAME, null, properties, "./", null, versionConfig, null);
         tools.setInstallations(installation);