CORDA-1354 Check for jars in nested folders (to add in classpath) (#2981)

+ edge cases (logging if we don't have permission to jar folders)

node/src/main/java/CordaCaplet.java

@@ -4,8 +4,6 @@
 
 import com.typesafe.config.*;
 import sun.misc.Signal;
-import sun.misc.SignalHandler;
-
 import java.io.File;
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -80,9 +78,11 @@ public class CordaCaplet extends Capsule {
         if (ATTR_APP_CLASS_PATH == attr) {
             T cp = super.attribute(attr);
 
-            (new File(baseDir, "cordapps")).mkdir();
+            File cordappsDir = new File(baseDir, "cordapps");
-            // Add additional directories of JARs to the classpath (at the end). e.g. for JDBC drivers
+            // Create cordapps directory if it doesn't exist.
-            augmentClasspath((List<Path>) cp, new File(baseDir, "cordapps"));
+            requireCordappsDirExists(cordappsDir);
+            // Add additional directories of JARs to the classpath (at the end), e.g., for JDBC drivers.
+            augmentClasspath((List<Path>) cp, cordappsDir);
             try {
                 List<String> jarDirs = nodeConfig.getStringList("jarDirs");
                 log(LOG_VERBOSE, "Configured JAR directories = " + jarDirs);
@@ -128,24 +128,58 @@ public class CordaCaplet extends Capsule {
     }
 
     private void augmentClasspath(List<Path> classpath, File dir) {
-        if (dir.exists()) {
+        try {
-            File[] files = dir.listFiles();
+            if (dir.exists()) {
-            for (File file : files) {
+                // The following might return null if the directory is not there (we check this already) or if an I/O error occurs.
+                for (File file : dir.listFiles()) {
+                    addToClasspath(classpath, file);
+                }
+            } else {
+                log(LOG_VERBOSE, "Directory to add in Classpath was not found " + dir.getAbsolutePath());
+            }
+        } catch (SecurityException | NullPointerException e) {
+            log(LOG_QUIET, e);
+        }
+    }
+
+    private void requireCordappsDirExists(File dir) {
+        try {
+            if (!dir.mkdir() && !dir.exists()) { // It is unlikely to enter this if-branch, but just in case.
+                logOnFailedCordappDir();
+                throw new RuntimeException("Cordapps dir could not be created"); // Let Capsule handle the error (log error, clean up, die).
+            }
+        }
+        catch (SecurityException | NullPointerException e) {
+            logOnFailedCordappDir();
+            throw e; // Let Capsule handle the error (log error, clean up, die).
+        }
+    }
+
+    private void logOnFailedCordappDir() {
+        log(LOG_VERBOSE, "Cordapps dir could not be created");
+    }
+
+    private void addToClasspath(List<Path> classpath, File file) {
+        try {
+            if (file.canRead()) {
                 if (file.isFile() && isJAR(file)) {
                     classpath.add(file.toPath().toAbsolutePath());
+                } else if (file.isDirectory()) { // Search in nested folders as well. TODO: check for circular symlinks.
+                    augmentClasspath(classpath, file);
                 }
+            } else {
+                log(LOG_VERBOSE, "File or directory to add in Classpath could not be read " + file.getAbsolutePath());
             }
+        } catch (SecurityException | NullPointerException e) {
+            log(LOG_QUIET, e);
         }
     }
 
     @Override
     protected void liftoff() {
         super.liftoff();
-        Signal.handle(new Signal("INT"), new SignalHandler() {
+        Signal.handle(new Signal("INT"), signal -> {
-            @Override
+            // Disable Ctrl-C for this process, so the child process can handle it in the shell instead.
-            public void handle(Signal signal) {
-                // Disable Ctrl-C for this process, so the child process can handle it in the shell instead.
-            }
         });
     }