https://github.com/google/guava/guava: Guava is a suite of core and expanded libraries that include utility classes, google's collections, io classes, and much much more. 
public final class com.google.common.io.PatternFilenameFilter implements java.io.FilenameFilter
  minor version: 0
  major version: 59
  flags: flags: (0x0031) ACC_PUBLIC, ACC_FINAL, ACC_SUPER
  this_class: com.google.common.io.PatternFilenameFilter
  super_class: java.lang.Object
{
  private final java.util.regex.Pattern pattern;
    descriptor: Ljava/util/regex/Pattern;
    flags: (0x0012) ACC_PRIVATE, ACC_FINAL

  public void <init>(java.lang.String);
    descriptor: (Ljava/lang/String;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // com.google.common.io.PatternFilenameFilter this
        start local 1 // java.lang.String patternStr
         0: .line 46
            aload 0 /* this */
            aload 1 /* patternStr */
            invokestatic java.util.regex.Pattern.compile:(Ljava/lang/String;)Ljava/util/regex/Pattern;
            invokespecial com.google.common.io.PatternFilenameFilter.<init>:(Ljava/util/regex/Pattern;)V
         1: .line 47
            return
        end local 1 // java.lang.String patternStr
        end local 0 // com.google.common.io.PatternFilenameFilter this
      LocalVariableTable:
        Start  End  Slot        Name  Signature
            0    2     0        this  Lcom/google/common/io/PatternFilenameFilter;
            0    2     1  patternStr  Ljava/lang/String;
    MethodParameters:
            Name  Flags
      patternStr  

  public void <init>(java.util.regex.Pattern);
    descriptor: (Ljava/util/regex/Pattern;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // com.google.common.io.PatternFilenameFilter this
        start local 1 // java.util.regex.Pattern pattern
         0: .line 54
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 55
            aload 0 /* this */
            aload 1 /* pattern */
            invokestatic com.google.common.base.Preconditions.checkNotNull:(Ljava/lang/Object;)Ljava/lang/Object;
            checkcast java.util.regex.Pattern
            putfield com.google.common.io.PatternFilenameFilter.pattern:Ljava/util/regex/Pattern;
         2: .line 56
            return
        end local 1 // java.util.regex.Pattern pattern
        end local 0 // com.google.common.io.PatternFilenameFilter this
      LocalVariableTable:
        Start  End  Slot     Name  Signature
            0    3     0     this  Lcom/google/common/io/PatternFilenameFilter;
            0    3     1  pattern  Ljava/util/regex/Pattern;
    MethodParameters:
         Name  Flags
      pattern  

  public boolean accept(java.io.File, java.lang.String);
    descriptor: (Ljava/io/File;Ljava/lang/String;)Z
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=3, args_size=3
        start local 0 // com.google.common.io.PatternFilenameFilter this
        start local 1 // java.io.File dir
        start local 2 // java.lang.String fileName
         0: .line 60
            aload 0 /* this */
            getfield com.google.common.io.PatternFilenameFilter.pattern:Ljava/util/regex/Pattern;
            aload 2 /* fileName */
            invokevirtual java.util.regex.Pattern.matcher:(Ljava/lang/CharSequence;)Ljava/util/regex/Matcher;
            invokevirtual java.util.regex.Matcher.matches:()Z
            ireturn
        end local 2 // java.lang.String fileName
        end local 1 // java.io.File dir
        end local 0 // com.google.common.io.PatternFilenameFilter this
      LocalVariableTable:
        Start  End  Slot      Name  Signature
            0    1     0      this  Lcom/google/common/io/PatternFilenameFilter;
            0    1     1       dir  Ljava/io/File;
            0    1     2  fileName  Ljava/lang/String;
    RuntimeVisibleTypeAnnotations: 
      METHOD_FORMAL_PARAMETER
        org.checkerframework.checker.nullness.qual.Nullable()
    MethodParameters:
          Name  Flags
      dir       
      fileName  
}
SourceFile: "PatternFilenameFilter.java"
    RuntimeInvisibleAnnotations: 
      com.google.common.annotations.Beta()
      com.google.common.annotations.GwtIncompatible()