ADDITIONAL SYSTEM INFORMATION :
Window 10
** java.vendor = Oracle Corporation
** java.version = 11.0.1
** java.vm.name = OpenJDK 64-Bit Server VM

A DESCRIPTION OF THE PROBLEM :
We use the FontMetrics object to help position text on our customers diagrams where they want it.
For some fonts, the values obtained from the FontMetrics object remain the same compared with Java 8
For many other fonts, in Java 11, we can get different values for Ascent,Descent,Height,Leading,MaxAdvance,MaxAscent&MaxDescent values.
This causes our customer's 'released diagrams' (diagrams that should not be changing) to look different.

REGRESSION : Last worked in version 8u172

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Compile & Run the provided code in Java 8.
Compile & Run the provided code in Java 11.
Note that for MANY fonts, we get different values for Ascent,Descent,Height,Leading,MaxAdvance,MaxAscent&MaxDescent values.

Running the provided code in Java 12ea produces the same result.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
We should get the same values as we did in Java 8 for all fonts =>

** java.vendor = Oracle Corporation
** java.version = 1.8.0_172
** java.vm.name = Java HotSpot(TM) 64-Bit Server VM

Name Family Style Size Ascent Descent Height Leading MaxAdvance MaxAscent MaxDescent stringWidth
Arial Arial 0 12.0 12 3 15 0 24 12 3 51
Arial Arial 0 24.0 23 5 29 1 48 23 5 101
Arial Arial 0 48.0 45 10 56 1 96 45 10 199
Arial Black Arial Black 0 12.0 14 4 18 0 21 14 4 61
Arial Black Arial Black 0 24.0 27 8 35 0 42 27 8 123
Arial Black Arial Black 0 48.0 53 15 68 0 83 53 15 245
Arial Bold Arial 0 12.0 12 3 15 0 24 12 3 51
Arial Bold Arial 0 24.0 23 5 29 1 48 23 5 109
Arial Bold Arial 0 48.0 45 10 56 1 96 45 10 215
Arial Bold Italic Arial 0 12.0 12 3 15 0 16 12 3 53
Arial Bold Italic Arial 0 24.0 23 5 29 1 32 23 5 106
Arial Bold Italic Arial 0 48.0 45 10 56 1 64 45 10 215
Arial Italic Arial 0 12.0 12 3 15 0 16 12 3 52
Arial Italic Arial 0 24.0 23 5 29 1 32 23 5 100
Arial Italic Arial 0 48.0 45 10 56 1 64 45 10 202
Arial Narrow Arial Narrow 0 12.0 12 3 15 0 13 12 3 41
Arial Narrow Arial Narrow 0 24.0 23 6 29 0 26 23 6 80
Arial Narrow Arial Narrow 0 48.0 45 11 56 0 51 45 11 165
Arial Narrow Bold Arial Narrow 0 12.0 12 3 15 0 13 12 3 44
Arial Narrow Bold Arial Narrow 0 24.0 23 6 29 0 26 23 6 87
Arial Narrow Bold Arial Narrow 0 48.0 45 11 56 0 51 45 11 177
Arial Narrow Bold Italic Arial Narrow 0 12.0 12 3 15 0 13 12 3 44
Arial Narrow Bold Italic Arial Narrow 0 24.0 23 6 29 0 26 23 6 87
Arial Narrow Bold Italic Arial Narrow 0 48.0 45 11 56 0 51 45 11 177
Arial Narrow Italic Arial Narrow 0 12.0 12 3 15 0 13 12 3 39
Arial Narrow Italic Arial Narrow 0 24.0 23 6 29 0 26 23 6 81
Arial Narrow Italic Arial Narrow 0 48.0 45 11 56 0 51 45 11 165
Arial Rounded MT Bold Arial Rounded MT Bold 0 12.0 12 3 15 0 15 12 3 53
Arial Rounded MT Bold Arial Rounded MT Bold 0 24.0 23 6 29 0 29 23 6 110
Arial Rounded MT Bold Arial Rounded MT Bold 0 48.0 46 11 57 0 58 46 11 216
Arial Unicode MS Arial Unicode MS 0 12.0 13 4 17 0 28 13 4 52
Arial Unicode MS Arial Unicode MS 0 24.0 26 7 33 0 55 26 7 98
Arial Unicode MS Arial Unicode MS 0 48.0 52 13 65 0 109 52 13 202
ACTUAL -
We get different values for FontMetrics, for many fonts in Java 11 & 12ea=>

** java.vendor = Oracle Corporation
** java.version = 11.0.1
** java.vm.name = OpenJDK 64-Bit Server VM

Name Family Style Size Ascent Descent Height Leading MaxAdvance MaxAscent MaxDescent stringWidth
Arial Arial 0 12.0 11 3 14 0 24 11 3 51
Arial Arial 0 24.0 22 6 28 0 48 22 6 101
Arial Arial 0 48.0 44 11 56 1 96 44 11 199
Arial Black Arial Black 0 12.0 14 4 18 0 21 14 4 61
Arial Black Arial Black 0 24.0 27 8 35 0 41 27 8 123
Arial Black Arial Black 0 48.0 53 15 68 0 83 53 15 245
Arial Bold Arial 0 12.0 11 3 14 0 24 11 3 51
Arial Bold Arial 0 24.0 22 6 28 0 48 22 6 109
Arial Bold Arial 0 48.0 44 11 56 1 96 44 11 215
Arial Bold Italic Arial 0 12.0 11 3 14 0 16 11 3 53
Arial Bold Italic Arial 0 24.0 22 6 28 0 32 22 6 106
Arial Bold Italic Arial 0 48.0 44 11 56 1 64 44 11 215
Arial Italic Arial 0 12.0 11 3 14 0 16 11 3 52
Arial Italic Arial 0 24.0 22 6 28 0 32 22 6 100
Arial Italic Arial 0 48.0 44 11 56 1 64 44 11 202
Arial Narrow Arial Narrow 0 12.0 12 3 15 0 13 12 3 41
Arial Narrow Arial Narrow 0 24.0 23 6 29 0 25 23 6 80
Arial Narrow Arial Narrow 0 48.0 45 11 56 0 51 45 11 165
Arial Narrow Bold Arial Narrow 0 12.0 12 3 15 0 13 12 3 44
Arial Narrow Bold Arial Narrow 0 24.0 23 6 29 0 25 23 6 87
Arial Narrow Bold Arial Narrow 0 48.0 45 11 56 0 51 45 11 177
Arial Narrow Bold Italic Arial Narrow 0 12.0 12 3 15 0 13 12 3 44
Arial Narrow Bold Italic Arial Narrow 0 24.0 23 6 29 0 25 23 6 87
Arial Narrow Bold Italic Arial Narrow 0 48.0 45 11 56 0 51 45 11 177
Arial Narrow Italic Arial Narrow 0 12.0 12 3 15 0 13 12 3 39
Arial Narrow Italic Arial Narrow 0 24.0 23 6 29 0 25 23 6 81
Arial Narrow Italic Arial Narrow 0 48.0 45 11 56 0 51 45 11 165
Arial Rounded MT Bold Arial Rounded MT Bold 0 12.0 12 3 15 0 15 12 3 53
Arial Rounded MT Bold Arial Rounded MT Bold 0 24.0 23 6 29 0 29 23 6 110
Arial Rounded MT Bold Arial Rounded MT Bold 0 48.0 46 11 57 0 58 46 11 216
Arial Unicode MS Arial Unicode MS 0 12.0 13 4 17 0 27 13 4 52
Arial Unicode MS Arial Unicode MS 0 24.0 26 7 33 0 54 26 7 98
Arial Unicode MS Arial Unicode MS 0 48.0 52 13 65 0 108 52 13 202

---------- BEGIN SOURCE ----------
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics2D;
import java.awt.GraphicsEnvironment;
import java.awt.image.BufferedImage;
import java.util.Arrays;
import java.util.List;

public class FontMetricsIssue
{

private static final List<Float> sizes = Arrays.asList(12.0f, 24.0f, 48.0f);

public static void main(String[] args)
{
titles();
List<Font> fontList = getFonts();
fontList
.stream()
.filter(FontMetricsIssue::isArial) // comment out to try with ALL fonts
.sorted(FontMetricsIssue::comparitor)
.forEach(FontMetricsIssue::reportFontMetrics);
}

private static boolean isArial(Font font)
{
return font.getName().contains("Arial");
}

private static List<Font> getFonts()
{
GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
Font[] fonts = ge.getAllFonts();
return Arrays.asList(fonts);
}

private static void titles()
{
System.err.println( "** java.vendor = " + System.getProperty("java.vendor"));
System.err.println( "** java.version = " + System.getProperty("java.version"));
System.err.println( "** java.vm.name = " + System.getProperty("java.vm.name"));
System.err.println();
System.err.println();

System.err.print("Name");
System.err.print("\tFamily");
System.err.print("\tStyle");
System.err.print("\tSize");
System.err.print("\tAscent");
System.err.print("\tDescent");
System.err.print("\tHeight");
System.err.print("\tLeading");
System.err.print("\tMaxAdvance");
System.err.print("\tMaxAscent");
System.err.print("\tMaxDescent");
System.err.print("\tstringWidth");
System.err.println();
}

private static int comparitor(Font f1, Font f2)
{
int rval = f1.getFontName().compareTo(f2.getFontName());
if (rval != 0) {
return rval;
}
rval = f1.getFamily().compareTo(f2.getFamily());
if (rval != 0) {
return rval;
}
rval = f1.getName().compareTo(f2.getName());
if (rval != 0) {
return rval;
}
Integer i1 = f1.getStyle();
Integer i2 = f1.getStyle();
return i1.compareTo(i2);
}

private static void reportFontMetrics(Font baseFont)
{
sizes
.stream()
.forEach(size -> reportFontMetrics(baseFont, size));
}

private static void reportFontMetrics(Font baseFont, Float size)
{
Font font = baseFont.deriveFont(size);
BufferedImage img = new BufferedImage(100, 100,
BufferedImage.TYPE_INT_ARGB);
Graphics2D g2d = img.createGraphics();
FontMetrics metrics = g2d.getFontMetrics(font);
System.err.print(font.getName());
System.err.print("\t" + font.getFamily());
System.err.print("\t" + font.getStyle());
System.err.print("\t" + size);
System.err.print("\t" + metrics.getAscent());
System.err.print("\t" + metrics.getDescent());
System.err.print("\t" + metrics.getHeight());
System.err.print("\t" + metrics.getLeading());
System.err.print("\t" + metrics.getMaxAdvance());
System.err.print("\t" + metrics.getMaxAscent());
System.err.print("\t" + metrics.getMaxDescent());
System.err.print("\t" + metrics.stringWidth("Hello you"));
System.err.println();
}
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
None

It looks like the class T2KFontScaler was removed in Java 11 and FreetypeFontScaler is used instead, so no workaround.

FREQUENCY : always