Unify printing exception stack-traces to String

org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/batch/Main.java

@@ -46,7 +46,6 @@
 import java.io.OutputStreamWriter;
 import java.io.PrintWriter;
 import java.io.StringReader;
-import java.io.StringWriter;
 import java.io.UnsupportedEncodingException;
 import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
@@ -574,12 +573,7 @@ public void logCommandLineArguments(String[] commandLineArguments) {
 		 * @param e the given exception to log
 		 */
 		public void logException(Exception e) {
-			StringWriter writer = new StringWriter();
-			PrintWriter printWriter = new PrintWriter(writer);
-			e.printStackTrace(printWriter);
-			printWriter.flush();
-			printWriter.close();
-			final String stackTrace = writer.toString();
+			final String stackTrace = Util.getStackTrace(e).toString();
 			if ((this.tagBits & Logger.XML) != 0) {
 				LineNumberReader reader = new LineNumberReader(new StringReader(stackTrace));
 				String line;

org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/problem/ProblemReporter.java

@@ -81,13 +81,11 @@
 package org.eclipse.jdt.internal.compiler.problem;
 
 import java.io.CharConversionException;
-import java.io.PrintWriter;
-import java.io.StringWriter;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
-import java.util.Set;
 import java.util.Map;
+import java.util.Set;
 import java.util.function.Supplier;
 import java.util.stream.Collectors;
 
@@ -1455,18 +1453,10 @@ public void cannotReadSource(CompilationUnitDeclaration unit, AbortCompilationUn
 				0);
 		return;
 	}
-	StringWriter stringWriter = new StringWriter();
-	PrintWriter writer = new PrintWriter(stringWriter);
 	if (verbose) {
-		abortException.exception.printStackTrace(writer);
-		System.err.println(stringWriter.toString());
-		stringWriter = new StringWriter();
-		writer = new PrintWriter(stringWriter);
-	}
-	writer.print(abortException.exception.getClass().getName());
-	writer.print(':');
-	writer.print(abortException.exception.getMessage());
-	String exceptionTrace = stringWriter.toString();
+		System.err.println(Util.getStackTrace(abortException.exception));
+	}
+	String exceptionTrace = abortException.exception.getClass().getName() + ':' + abortException.exception.getMessage();
 	String[] arguments = new String[]{ fileName, exceptionTrace };
 	this.handle(
 			IProblem.CannotReadSource,

org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/util/Util.java

@@ -23,7 +23,7 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.PrintWriter;
-import java.io.StringWriter;
+import java.io.Writer;
 import java.net.URI;
 import java.nio.ByteBuffer;
 import java.nio.CharBuffer;
@@ -558,9 +558,7 @@ private static boolean startsWith(byte[] a, byte[] start) {
 	 * @return one line summary for an exception
 	 */
 	public static String getExceptionSummary(Throwable exception) {
-		StringWriter stringWriter = new StringWriter();
-		exception.printStackTrace(new PrintWriter(stringWriter));
-		StringBuffer buffer = stringWriter.getBuffer();
+		CharSequence buffer = getStackTrace(exception);
 		StringBuffer exceptionBuffer = new StringBuffer(50);
 		exceptionBuffer.append(exception.toString());
 		// only keep leading frame portion of the trace (i.e. line no. 2 from the stacktrace)
@@ -569,7 +567,7 @@ public static String getExceptionSummary(Throwable exception) {
 				case '\n':
 				case '\r' :
 					if (line2Start > 0) {
-						exceptionBuffer.append(' ').append(buffer.substring(line2Start, i));
+						exceptionBuffer.append(' ').append(buffer.subSequence(line2Start, i));
 						break lookupLine2;
 					}
 					lineSep++;
@@ -588,6 +586,30 @@ public static String getExceptionSummary(Throwable exception) {
 		return exceptionBuffer.toString();
 	}
 
+	public static CharSequence getStackTrace(Throwable exception) {
+		StringBuilder builder = new StringBuilder();
+		exception.printStackTrace(new PrintWriter(new Writer() {
+			@Override
+			public void write(char[] cbuf, int off, int len) throws IOException {
+				builder.append(cbuf, off, len);
+			}
+
+			@Override
+			public void write(String str, int off, int len) throws IOException {
+				builder.append(str, off, len);
+			}
+
+			@Override
+			public void flush() throws IOException { // nothing to do
+			}
+
+			@Override
+			public void close() throws IOException { // nothing to do
+			}
+		}));
+		return builder;
+	}
+
 	public static int getLineNumber(int position, int[] lineEnds, int g, int d) {
 		if (lineEnds == null)
 			return 1;

org.eclipse.jdt.core/dom/org/eclipse/jdt/core/dom/ASTParser.java

@@ -16,7 +16,6 @@
 package org.eclipse.jdt.core.dom;
 
 import java.io.PrintWriter;
-import java.io.StringWriter;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
@@ -1136,11 +1135,8 @@ private ASTNode internalCreateAST(IProgressMonitor monitor) {
 								}
 							} catch(JavaModelException e) {
 								// an error occured accessing the java element
-								StringWriter stringWriter = new StringWriter();
-								try (PrintWriter writer = new PrintWriter(stringWriter)) {
-									e.printStackTrace(writer);
-								}
-								throw new IllegalStateException(String.valueOf(stringWriter.getBuffer()));
+								CharSequence stackTrace = org.eclipse.jdt.internal.compiler.util.Util.getStackTrace(e);
+								throw new IllegalStateException(stackTrace.toString());
 							}
 						}
 					}
@@ -1206,11 +1202,8 @@ private ASTNode internalCreateAST(IProgressMonitor monitor) {
 							sourceUnit = new BasicCompilationUnit(sourceString.toCharArray(), Util.toCharArrays(packageFragment.names), fileNameString, this.typeRoot);
 						} catch(JavaModelException e) {
 							// an error occured accessing the java element
-							StringWriter stringWriter = new StringWriter();
-							try (PrintWriter writer = new PrintWriter(stringWriter)) {
-								e.printStackTrace(writer);
-							}
-							throw new IllegalStateException(String.valueOf(stringWriter.getBuffer()));
+							CharSequence stackTrace = org.eclipse.jdt.internal.compiler.util.Util.getStackTrace(e);
+							throw new IllegalStateException(stackTrace.toString());
 						}
 					} else if (this.rawSource != null) {
 						needToResolveBindings =